Calculator Program does not compile

Question

I wrote a program that implements a simple calculator. However, it does not compile. The compiler says that there are 22 errors, and I don't know why.

Desired behavior:

1. Asks user about the desired operation
2. Asks user about the parameters
3. Outputs result

Specific problem or error:

Compilation errors at any occurrence of cin,cout, endl, case and break

Minimal, Complete, and Verifiable example:

#include <iostream>
int main()
{
    float area, r, l, h, b;
    int choice;
    cout<<"\n area of?";
    cout<<"\n[1]square \n[2]rectangle \n[3]circle \n[4]triangle"<<endl;
    cin>>choice;
    switch(choice);
    {
    case 1:
        cout<<"enter length"<<endl;
        cin>>l;
        area=l*l;
        cout<<area<<endl;
        break;
    case 2:
        cout<<"enter height"<<endl;
        cin>>h;
        cout<<"enter length"<<endl;
        cin>>l;
        area=l*h;
        cout<<area<<endl;
        break;
    case 3:
        cout<<"enter radius"<<endl;
        cin>>r;
        area=r*r*3.14;
        cout<<area<<endl;
        break;
    case 4:
        cout<<"enter height"<<endl;
        cin>>h;
        cout<<"enter breadth"<<endl;
        cin>>b;
        area=h*b*0.5;
        cout<<area<<endl;
        break;
    }

    return 0;
}

Answer 1

The are two errors (compile time errors, at least). First of all, cin, cout and endl are not known, you have to write them as std::cin, std::cout and std::endl.

The second problem is here:

switch (choice);

Remove that semicolon and it's fine. The reson why it's not working with the semicolon is because then switch (choice); is its own one and done deal, and the statements after it don't make sense without it.

Also, although it's not causing any compile time errors, I would highly recommend that you indent your code properly. mjcs edited the code you provided for you, it now looks much nicer and it is much easier to find the errors this way. In a big program, it is absolutely vital that the code is indented well, otherwise it's very hard to work with.