calculator by using switch statement

#include "stdafx.h"

#include<iostream>

using namespace std;

void main()

{

float n1,n2,s;

char ch;

cout<<"ENter the values"<<endl;

cin>>n1;

cout<<"ENter the operator"<<endl;

cin>>ch;

cout<<"ENter the 2nd values"<<endl;

cin>>n2;

switch(ch)

{

case '+':

       s=n1+n2;

       break;

       case '-':

       s=n1-n2;

       break;

       case '*':

    s=n1*n2;

       break;

       case '/':

       s=n1/n2;

       break;

default:

       cout<<"invalid character "<<endl;

}

       if (ch=='+'||ch=='-'||ch=='*'||ch=='/')

              cout<<n1<<ch<<n2<<"="<<s<<endl;

system("pause");

}