整数转化为任意n进制的字符串

 

//整数转化为任意n进制的字符串（1<n<37）

#include <stdlib.h>

#include <stdio.h>

#include<string.h>

   

void itob(int n, char s[], int b);

void reverse(char s[]);

 

int main(void)

{

    char buffer[10];

    int i;

   

    for ( i = 2; i <= 20; ++i )

       {

        itob(255, buffer, i);

        printf("Decimal 255 in base %-2d : %s\n", i, buffer);

    }

    return 0;

}

 

void itob(int n, char s[], int b)

{

    static char digits[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    int i, sign;

   

    if ( b < 2 || b > 36 ) {

        fprintf(stderr, "EX3_5: Cannot support base %d\n", b);

        exit(EXIT_FAILURE);//exit函数使程序正常终止

    }

    //判断正负，负数变正数

    if ((sign = n) < 0)

        n = -n;

    i = 0;

       //求对应的字符

    do {

                 s[i++] = digits[n % b];

              } while ((n /= b) > 0);

    if (sign < 0)

        s[i++] = '-';

    s[i] = '\0';

    reverse(s);//字符串转置

}

 

void reverse(char s[])

{

    int c, i, j;

    for ( i = 0, j = strlen(s)-1; i < j; i++, j--) {

        c = s[i];

        s[i] = s[j];

        s[j] = c;

    }

}