Thread: Question concerning functions

  1. #1
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    Question concerning functions

    I'm currently on the functions tutorial, but there's one thing that I just can't understand how to do (which it doesn't explain how, but says that it's possible and a good idea to use). How would I go about making a function to actually repeat a certain block of code a certain amount of times? The only type of functions that the tutorial explains is a function that will accept two arguments, and return an integer. Also note that I'm not asking how to do this for a specific program; I just need to know how I'd go about doing this.

    Also, if possible, please write out both in code and explaining it to me so I can look at the structure of the code if I don't understand something.

  2. #2
    C++ Witch laserlight's Avatar
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    Have you checked out loops yet?
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  3. #3
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    You just call the function multiple times:
    Code:
    #include <iostream>
    
    using namespace std;
    
    int mult ( int x, int y );
    
    int main()
    {
      int x;
      int y;
      
      cout<<"Please input two numbers to be multiplied: ";
      cin>> x >> y;
      cin.ignore();
      cout<<"The product of your two numbers is "<< mult ( x, y ) <<"\n";
    
      cout<<"Please input two numbers to be multiplied: ";
      cin>> x >> y;
      cin.ignore();
      cout<<"The product of your two numbers is "<< mult ( x, y ) <<"\n";
    
      cout<<"Please input two numbers to be multiplied: ";
      cin>> x >> y;
      cin.ignore();
      cout<<"The product of your two numbers is "<< mult ( x, y ) <<"\n";
    
      cin.get();
    }
    
    int mult ( int x, int y )
    {
      return x * y;
    }
    or, if you know for loops:
    Code:
    #include <iostream>
    
    using namespace std;
    
    int mult ( int x, int y );
    
    int main()
    {
      int x;
      int y;
    
      for (int i = 0; i < 40; ++i)
      {  
        cout<<"Please input two numbers to be multiplied: ";
        cin>> x >> y;
        cin.ignore();
        cout<<"The product of your two numbers is "<< mult ( x, y ) <<"\n";
        cin.get();
      }
    }
    
    int mult ( int x, int y )
    {
      return x * y;
    }

  4. #4
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    K, thanks. Yeah, I've done the loops tutorial, I just forgot it already >.<.

  5. #5
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    Kind of confused though; when I typed up that code it won't loop regardless of the fact that it looks almost exactly like yours (the only differences are spaces between code).

    The code I'm confused about:

    Code:
    #include <iostream>
    
    using namespace std;
    
    int mult ( int x, int y );
    
    int main()
    {
        int x;
        int y;
        for ( int x=0; x < 73; x++ )
        {
        cout<<"Please input two numbers to be multiplied.\n";
        cin>> x >> y;
        cin.ignore();
        cout<<"The product of your two numbers is "<< mult ( x, y ) <<"\n";
        cin.get();
        }
    }
    int mult ( int x, int y )
    {
              return x * y;
    }
    Any idea why it won't loop?

  6. #6
    C++ Witch laserlight's Avatar
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    x is your look index, but you also use it in your loop. Use some other variable for the loop index.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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