My First Program

I've finally been able to write my first half usefull C++ program there are a few thing I would like to add but at the moment I don't know enough to be able to add them .

I have some problems with the code below, when you choose to add and enter the first number etc. then when the answer is displayed the else statement which I added to the program is executed even though I don't want it to be, any ideas?

Code:

#include <iostream>

int main()
{
    
    int unsigned short DoAddOrMinus;
    int long FirstNumber;
    int long SecondNumber;
    
    std::cout << "What would you like to do?\n";
    
    //This is the code for the menu
    std::cout << "1 - Add\n2 - Subtract\n\n";
    
    std::cout << "Please make your selection: ";
    std::cin >>  DoAddOrMinus;
    
    //This is the if statement which performs addition
    if (DoAddOrMinus == 1)
    {
       std::cout << "\n\nWhat is the first number you want to add: ";
       std::cin >> FirstNumber;
       
       std::cout << "What is the second number you want to add: ";
       std::cin >> SecondNumber;
       std::cin.ignore(80,'\n');
       std::cout << "\n\n";
       
       std::cout << "The answer is: " << FirstNumber + SecondNumber << "\n";
    }   
    
    //This is the code which preforms subtraction
    if (DoAddOrMinus == 2)
    {
       std::cout << "\n\nWhat is the first number you want to subtract: ";
       std::cin >> FirstNumber;
       
       std::cout << "What is the second number you want to subtract: ";
       std::cin >> SecondNumber;
       std::cin.ignore(80,'\n');
       std::cout << "\n\n";
       
       std::cout << "The answer is: " << FirstNumber - SecondNumber << "\n";
    }
    
    //This is the code which is activated when someone does not enter a number from the menu
    else
    {
        std::cout << "You should have entered a number from the menu.\n";
    }
    
    std::cin.get();
    return 0;
    
}

Read the tutorial about switches they allow you to make long if statements.
Here is an example of my code:

Code:

#include <iostream>

    int multiply(int x,int y)
    {
    return x*y;
    }
    
    int divide(int x, int y)
    {
    return x/y;
    }
    
    int add(int x, int y)
    {
    return x+y;
    }
    
    int subtract(int x, int y)
    {
    return x-y;
    }

using namespace std;

int main()
{
    char op='c';
    int x,y;
    while (op!='e')
    {
    cout<<"What operation would you like to perform add(+), subtract(-),divide(/),multiply(*), (e)exit?";
    cin>> op;
    switch(op)
    {
    case '+':
    cout<<"Enter the numbers you would like to add."<<endl;
    cin>>x;
    cin>>y;
    cout<<x<<"+"<<y<<"="<<add(x,y)<<endl;
    break;
    
    case'-':
    cout<<"Enter the numbers you would like to subtract."<<endl;
    cin>>x;
    cin>>y;
    cout<<x<<"-"<<y<<"="<<subtract(x,y)<<endl;
    break;
    
    case'/':
    cout<<"Enter the numbers you would like to divide."<<endl;
    cin>>x;
    cin>>y;
    cout<<x<<"/"<<y<<divide(x,y)<<endl;
    break;
    
    case'*':
    cout<<"Enter the numbers you would like to multiply."<<endl;
    cin>>x;
    cin>>y;
    cout<<x<<"*"<<y<<multiply(x,y)<<endl;
    break;
    case'e':
    return 0;
    default:
    cout<<"sorry, try again."<<endl;
    }
    }
    
    return 0;
}

case replaces if which makes everything a lot easier.
As for the else loop I don't know why it won't work.

Your else statement will only operate properly if DoAddOrMinus == 2 because that is the only if statement it is attached to. If DoAddOrMinus == 1 the applicable if statement will execute it's code. But the next if statement only evaluates DoAddOrMinus == 2, and anything else will trigger the else statement.

Hint...lookup the else if evaluation statement.

Code:

    if (DoAddOrMinus == 1)
    {
        // some code
    }   
    .
    .
    if (DoAddOrMinus == 2)  // See Hint above
    {
         // some code
    }
    
    //This is the code which is activated when someone does not enter a number from the menu
    else
    {
        // This else is a logic error
    }