test cases are not passing.
#include
using namespace std;
int main()
{
char ch;
a:
cin>>ch;
unsigned long int n,m,r;
switch(ch)
{
case '’:
cin>>n>>m;
r=nm;
cout<<r;
break;
case ‘/’:
cin>>n>>m;
float q;
q=(float)n/m;
cout<<q;
break;
case '+':
cin>>n>>m;
r=n+m;
cout<<r;
break;
case '-':
cin>>n>>m;
r=n-m;
cout<<r;
break;
case '%':
cin>>n>>m;
if(m!=0)
r=n%m;
cout<<r;
break;
case 'x':
exit(0);
break;
case 'X':
exit(0);
break;
default:
cout<<"Invalid operation. Try again";
goto a;
break;
}
return 0;
}