Bitwise Operations using C++

#include
#include
#include void dectobi(int p)
{
int b,i,x,d;
for(i=31;i>=0;i--)
{
d=1<<i;
b=p&d;
if(b==0)
printf("0");
else
printf("1");
}
} 

void main()
{

int i,j,k,ch,n,m,a;
char cho;
clrscr();
do
{
printf("enter a integer\n");
scanf("%d",&n);
dectobi(n);
printf("\n 1 for 1`s compliment");
printf("\n 2 for AND opertion");
printf("\n 3 for OR opertion");
printf("\n 4 for EX-OR opertion");
printf("\n 5 for LEFT SHIFT opertion");
printf("\n 6 for RIGHT SHIFT opertion");
printf("\n 7 for EXIT\n");
scanf("%d",&ch);
switch(ch)
{
case 1:
printf(" \n1`s compliment\n");
a=~n;
dectobi(a);
break;
case 2:
printf("enter intger\n");
scanf("%d",&m);
dectobi(m);
printf("after and\n");
a=n&m;
dectobi(a);
break;
case 3:
printf("enter intger\n");
scanf("%d",&m);
dectobi(m);
printf("after OR\n");
a=n|m;
dectobi(a);
break;
case 4:
printf("enter intger\n");
scanf("%d",&m);
dectobi(m);
printf("after EX-OR\n");
a=n^m ;
dectobi(a);
break;
case 5:
printf("enter the no by u want to LEFT SHIFT");
scanf("%d",&m);
a=n<<m;
printf("after LEFT SHIFT\n");
a=n<<1;
        dectobi(a);
break;
case 6:
printf("enter the no by u want to RIGHT SHIFT");
scanf("%d",&m);
a=n>>m;
printf("after RIGHT SHIFT\n");
dectobi(a);
break;
case 7:
exit(0);
}
flushall();
printf("\nwant to continue (y/n)");
scanf("%c",&cho);
}
while(cho!='n');

}