kolibrios-fun/contrib/kolibri-libc/source/stdlib/atoi.c

#include <stdlib.h>
#include <ctype.h>

/*
** atoi(s) - convert s to integer.
*/
int atoi(const char *s)
{
    int sign, n;
    while(isspace(*s)) ++s;
    sign = 1;
    
    switch(*s) {
        case '-': sign = -1;
        case '+': ++s;
    }
    
    n = 0;
    while(isdigit(*s)) n = 10 * n + *s++ - '0';
    return (sign * n);
}