Help to using Switch case in c++? : How do I use switch case in this code ??
I have tried several times , But I really do not know how to make it without error .
I don't know anywhere i put it ??

    #include<iostream.h>
    int x,y;
    int sum(int a,int b)
    {
    int c;
    c = a+b;
    return (c);
     }
    int sub (int a ,int b)
    {
    int c;
    c = a-b ;
    return (c);
     }
    int multi ( int a, int b )
    {
    int c ;
    c = a*b;
    return (c);
    }
    float div ( int a , int b)
    {
    float c;
    c = a/b ;
    return (c);
    }
    main()
    {
    cout<<"enter the value of x = ";
    cin>>x;
    cout<<"enter the value of y = ";
    cin>>y;
    cout<<"x + y  = "<< sum(x,y);
    cout<<"\n x - y  = "<< sub(x,y);
    cout<<"\n x * y  = "<< multi(x,y);
    cout<<"\n x /y  = "<< div (x,y);
    cin>>"\n";
     }