01  #include<stdio.h>
02  #include<stdlib.h>
03  
04  int main()
05  {
06   int i=0,j;
07   int dNum;
08   int bArr[20];
09  
10   printf("Enter Decimal No. : ");
11   scanf("%d",&dNum);
12  
13   if(dNum==0)
14   {
15    printf("Binary string is 0");
16    exit(0);
17   }
18  
19   while(dNum>0)
20   {
21    bArr[i]=dNum%2;
22    dNum=dNum/2;
23    i++;
24   }
25  
26   printf("Binary string is ");
27  
28   for(j=i-1;j>=0;j--)
29   {
30    printf("%d",bArr[j]);
31   }
32  
33   return 0;
34  }

 OUTPUT :
 
 Enter Decimal N. : 55
 Binary string is 110111