Implementing decimal binary output __c language in C language

As we all know, C in eight, decimal and hexadecimal can be easily implemented through%d,%o and%x, but only does not provide a fast way of binary output. Bo Master sorted out two kinds of simple implementation methods for reference. Method One: itoa function

The Itoa function converts a numeric value to a string and implements it by a specified conversion. (or use C to bring the code block HH)

#include <stdio.h>
#include <stdlib.h>
//Note You must call the Stdlib.h function library
int main (void) {
    int a=1000;
    Char str[30];
    Itoa (a,str,2);//2 is the conversion to 2-in-system
    printf ("%s", str);

    return 0;

Method Two: Short division

Short division, converting decimal to binary written calculation process is accomplished by simple code. There's no shortcut.

#include <stdio.h>
int main (void) {
    int a,b,k,i;
    int remainder[30];
    A remainder array is defined to collect the remainder of the short division and the reverse output of the stack.
    a=1000;
    k=0;
    while (a!=0) {
        b=a/2;
        k++;
        remainder[k]=a-b*2;
        A=A/2;
    };
    for (i=k;i>=1;i--) {
        printf ("%d", Remainder[i]); 

    return 0;