字符串2整数

#include <stdio.h>

int myatoi(const char *s)
{
        int res = 0;

        while (*s) {
                res = res*10 + (int)(*s++ - '0');
        }

        return (res);
}

int
main(void)
{
        char *s = "32150";

        printf("Result: %d\n", myatoi(s));

        return (0);
}