C program : How to convert Negative Decimal Number into Binary number

#include<stdio.h>
char * Decimal_to_Binary(int no){
int i;
static char Buffer[17];
for(i=8*sizeof(int)-1; i>=0; i--)
Buffer[15-i]=(no>>i&1)+'0';
return Buffer;
}
void main(){
int no;
printf("Enter the Negative Decimal Number: ");
scanf("%d",&no);
printf("%s",Decimal_to_Binary(no));
}

output:

Enter the Negative Decimal Number:  -1

1111 1111 1111 1111