This code compiles and takes the input. But then it does not show the result. I looked through but dont see any error. 

```
int main(int argc, char** argv) {

  int a,b;
  char c;
  int res=0;
  scanf("%d %c %d",&a,&c,&b);
  //printf("%d %c %d",a,c,b);
  if(c!='+' || c!='-' || c!='*' || c!='/' ){
    return NAN;
  }
  else{

    switch(c){
      case '+':
        res=a+b;
        break;
      case '-': 
        res=a-b;
        break;            
      case '*':
        res=(a)*(b);
        break;

      case '/':
        res= a/b;
        break;
      default:
        break;
    }
  }
  printf("result is %d\n",res);
  return (EXIT_SUCCESS);
}

```