The C Programming Language 练习题3-5

#include <stdio.h>

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

int main()
{
int n, b, i;
char c, s[31];
n = 56789;
b = 8;
itob(n, s, b);
i = 0;
while ((c = s[i]) != '\0')
printf("%c", s[i++]);
}

void itob(int n, char s[], int b)
{
int i, j, m;
char c;

i = 0;
do
{
j = n % b;
c = j + '0';
s[i++] = c;
n = n / b;
}
while (n > 0);
s[i] = '\0';
reverse(s);
}

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;
}
}