493 lines
7.0 KiB
C++
493 lines
7.0 KiB
C++
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#include "func.h"
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#include "parser.h"
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// token types
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#define DELIMITER 1
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#define VARIABLE 2
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#define NUMBER 3
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#define FUNCTION 4
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#define FINISHED 10
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// error codes
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#define ERR_BADFUNCTION -1
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#define ERR_BADNUMER -2
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#define ERR_GENERAL -3
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#define ERR_NOBRACKET -4
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#define ERR_BADVARIABLE -5
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#define ERR_OVERFLOW -6
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double __cdecl tg(double d)
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{
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return sin(d) / cos(d);
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}
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double __cdecl ctg(double d)
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{
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return cos(d) / sin(d);
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}
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double __cdecl exp(double x)
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{
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__asm {
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fld x
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FLDL2E
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FMUL
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FLD st(0)
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FLD1
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FXCH
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FPREM
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F2XM1
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fadd
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FSCALE
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FSTP st(1)
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}
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}
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double __cdecl log(double x)
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{
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//return 0.0;
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__asm {
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FLD1
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FLD x
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FYL2X
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FLDLN2
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FMUL
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}
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}
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double __cdecl sqrt(double x)
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{
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__asm {
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fld x
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fsqrt
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}
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}
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double __cdecl atan(double x)
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{
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return 0.0; // â ëîì
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}
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double pow(double x, double y)
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{
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return 0.0; // â ëîì, ïóñêàé ñ÷èòàþò ÷åðåõ exp è log
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}
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// represents general mathematical function
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typedef double(__cdecl*matfunc)(double);
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// used to link function name to the function
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typedef struct
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{
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char name[10];
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matfunc f;
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} func;
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// the list of functions
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const int max_func = 12;
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func functions[max_func] =
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{
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"", NULL,
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"sin", &sin,
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"cos", &cos,
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"exp", &exp,
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"sqrt", &sqrt,
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"log", &log,
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"tg", &tg,
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"ctg", &ctg,
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"arcsin", &asin,
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"arccos", &acos,
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"arctg", &atan,
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"abs", &fabs
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};
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// all delimiters
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const char *delim="+-*^/%=;(),><"; // not bad words
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// structure for most parser functions
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char token[80];
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int token_type;
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char *prog;
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double x_value;
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int code; // error code
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int isdelim(char c)
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{
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//return strchr(delim, c) != 0;
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for (int i = 0; i < 14; i++)
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if (c == delim[i])
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return 1;
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return 0;
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}
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int isdigit(char c)
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{
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return (c >= '0' && c <= '9');
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}
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int isalpha2(char c)
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{
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return ((c >= 'a' && c <= 'z')
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|| (c >= 'A' && c <= 'Z'));
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}
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int iswhite(char c)
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{
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return (c==' ' || c=='\t');
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}
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void serror(int code)
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{
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::code = code;
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// longjmp(j, code);
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}
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void set_exp(char *exp, double x)
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{
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prog = exp;
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x_value = x;
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}
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int get_token()
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{
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int tok;
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char *temp;
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(token_type) = 0;
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tok = 0;
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temp = (token);
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if (*(prog) == '\0')
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{
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*(token) = 0;
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tok = FINISHED;
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return ((token_type) = DELIMITER);
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}
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while (iswhite(*(prog))) ++(prog);
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if (isdelim(*(prog)))
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{
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*temp = *(prog);
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(prog)++;
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temp++;
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*temp = 0;
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return ((token_type) = DELIMITER);
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}
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if (isdigit(*(prog)))
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{
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while (!isdelim(*(prog)))
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*temp++=*(prog)++;
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*temp = '\0';
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return ((token_type) = NUMBER);
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}
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if (isalpha2(*(prog)))
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{
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while (!isdelim(*(prog)))
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*temp++=*(prog)++;
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(token_type) = VARIABLE;
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}
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*temp = '\0';
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if ((token_type) == VARIABLE)
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{
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tok = look_up((token));
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if (tok)
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(token_type) = FUNCTION;
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}
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return (token_type);
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}
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int sign(double d)
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{
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if (d > 0.0)
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return 1.0;
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if (d < 0.0)
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return -1.0;
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return 0.0;
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}
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void putback()
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{
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char *t;
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t = (token);
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for (;*t;t++)
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(prog)--;
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}
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int get_exp(double *hold)
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{
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int res;
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code = 0;
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// if (res = setjmp(j) != 0)
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// return code;
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get_token();
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if (!*(token))
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{
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return 0;
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}
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level2( hold);
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putback();
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return 0;
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}
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void level2(double *hold)
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{
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char op;
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double h;
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level3( hold);
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while ((op=*(token)) == '+' || op == '-')
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{
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get_token();
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level3( &h);
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arith(op, hold, &h);
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}
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}
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void level3(double *hold)
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{
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char op;
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double h;
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level4( hold);
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while ((op=*(token)) == '*' || op == '/' || op == '%')
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{
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get_token();
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level4( &h);
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arith( op, hold, &h);
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}
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}
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void level4(double *hold)
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{
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double h;
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level5( hold);
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if (*(token) == '^')
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{
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get_token();
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level5( &h);
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arith( '^', hold, &h);
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}
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}
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void level5(double *hold)
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{
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char op;
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op = 0;
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if (((token_type) == DELIMITER) && *(token) == '+' || *(token) == '-')
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{
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op = *(token);
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get_token();
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}
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level6( hold);
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if (op)
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unary(op, hold);
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}
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void level6(double *hold)
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{
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if ((*(token) == '(') && ((token_type) == DELIMITER))
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{
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get_token();
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level2( hold);
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if (*(token) != ')')
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serror( ERR_NOBRACKET);
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get_token();
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}
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else
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primitive( hold);
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}
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void calc_function(double *hold)
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{
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double d;
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int i;
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i = look_up(token);
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if (i == 0)
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serror(ERR_BADFUNCTION); // error
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get_token();
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if (*(token) != '(')
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serror(ERR_NOBRACKET); // error
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get_token();
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level2(hold);
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get_token();
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d = functions[i].f(*hold);
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*hold = (functions[i].f)(*hold);
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// else
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// serror( ERR_OVERFLOW);
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}
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void primitive(double *hold)
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{
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switch (token_type)
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{
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case VARIABLE:
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*hold = find_var(token);
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get_token();
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return;
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case NUMBER:
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//
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//*hold = atof((token));
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//if (sscanf(token, "%lf", hold) != 1)
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*hold = convert(token);
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if (*hold == ERROR)
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serror( ERR_BADNUMER);
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get_token();
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return;
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case FUNCTION:
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calc_function( hold);
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return;
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default: // error
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return;
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}
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}
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void arith(char op, double *r, double *h)
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{
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double t;
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switch(op)
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{
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case '-':
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*r = *r - *h;
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break;
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case '+':
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*r = *r + *h;
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break;
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case '*':
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*r = *r * *h;
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break;
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case '/':
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if (*h == 0)
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serror( ERR_OVERFLOW);
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else
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*r = (*r) / (*h);
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break;
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case '%':
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t = (*r) / (*h);
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*r = *r - (t * (*h));
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break;
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case '^':
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*r = pow(*r, *h);
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break;
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}
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}
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void unary(char op, double *r)
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{
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if (op == '-')
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*r = -(*r);
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}
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double find_var(char *s)
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{
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//return 0; // not imp
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//int i;
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//for (i = 0; i < kvar; i++)
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// if (strcmp(vars[i].name, s) == 0)
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// return vars[i].value;
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if (s[1] == '\0' && (s[0] == 'x' || s[0] == 'X'))
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//if (strcmp(s,"x") == 0 || strcmp(s,"X") == 0)
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return x_value;
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serror( ERR_BADVARIABLE);
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return 0; // to make compiler very happy
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//printf("\nPlease enter value for variable \"%s\": ", s);
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//scanf("%lf", &vars[kvar].value);
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//strcpy(vars[kvar].name, s);
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//kvar++;
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//return vars[kvar - 1].value;
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}
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bool strcmp(char *s1, char *s2)
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{
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int i;
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for (i = 0;;i++)
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{
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if (s1[i] == '\0')
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if (s2[i] == '\0')
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return 0;
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else
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return 1;
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else
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if (s2[i] == '\0')
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return 1;
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else
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{
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if (s1[i] != s2[i])
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return 1;
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}
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}
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}
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int look_up(char *s)
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{
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int i;
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for (i = 0; i < max_func; i++)
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if (strcmp(s, functions[i].name) == 0)
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return i;
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return 0; // search command/function name
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}
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/*
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void delete_white(char *buf)
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{
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int len = strlen(buf);
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char *d = (char *)malloc(len + 1);
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char *t = buf;
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strcpy(d, buf);
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d[len] = '\0';
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int i;
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for (i = 0; i < len; i++)
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if (!iswhite(d[i]))
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*t++=d[i];
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*t++='\0';
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free(d);
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}
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*/
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/*
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void main(void)
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{
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= (parser_struct)malloc(sizeof(parser_struct));
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double a;
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char buffer[256];
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printf("Enter expression: ");
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memset(buffer, 0, 256);
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gets(buffer);
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prog = buffer;
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delete_white(buffer);
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a = 0;
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x_value = 3;
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get_exp( &a);
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printf("result: %lg\n", a);
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getch();
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}
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*/ |