/* itob.c  - convert integer to binary
 *
 * Example for CS 313
 *
 * Daniel Scharstein
 *
 * to compile, use  gcc -W -Wall -o itob itob.c
 */

#include <stdio.h>
#include <string.h>

void reverse(char *s)           /* reverse string s */
{
    int i, j, temp;
    for (i=0, j=strlen(s)-1; i<j; i++, j--) {
        temp = s[j];
        s[j] = s[i];
        s[i] = temp;
    } 
}

void itob(unsigned int n, char *s) /* convert int to binary string */
{
    int i=0;
  
    do {
        s[i++] = n % 2 + '0';
    } while ((n /= 2) != 0);
    s[i] = '\0';
    reverse(s);
}

int main()
{
    char s[80];
    unsigned int n;

    do {
        printf("\nEnter a non-negative number (0 to quit): ");
        scanf("%u", &n);
        itob(n, s);
        printf("%s", s);
    } while (n > 0);
    printf("\n");

    return 0;
}