整数2字符串

#include <stdio.h>

void
strreverse(char *begin, char *end)
{
        char aux;

        while (end > begin) {
                aux = *end, *end-- = *begin, *begin++ = aux;
        }
}

void
myitoa(int value, char *str, int base)
{
        static char num[] = "0123456789abcedfghijklmnopqrstuvwxyz";
        char *wstr = str;
        int sign;

        if (base < 2 || base > 35) {
                *wstr = '\0';
                return ;
        }

        if ((sign = value) < 0)
                value = -value;

        do {
                *wstr++ = num[value%base];
        } while (value /= base);

        if (sign < 0)
                *wstr++ = '-';

        *wstr = '\0';

        strreverse(str, wstr-1);
}

void
myitoa2(int value, char *str, int base)
{
        char *wstr = str;
        int sign;

        if (base < 2 || base > 35) {
                *wstr = '\0';
                return ;
        }

        if ((sign = value) < 0)
                value = -value;

        while (value) {
                *wstr++ = value % base + '0';
                value /= base;
        }

        if (sign < 0)
                *wstr++ = '-';

        *wstr = '\0';

        strreverse(str, wstr-1);
}

int
main(void)
{
        int i = 13570;
        char res[6] = {0};

        myitoa(i, res, 10);
        printf("Result: %s\n", res);

        myitoa2(i, res, 10);
        printf("Result: %s\n", res);

        return (0);
}