Unreachable code in function main()

This is a discussion on Unreachable code in function main() within the C++ Programming forums, part of the General Programming Boards category; I just started programming, and I followed a tutorial to make a calculator. Once I was done, I wanted to ...

  1. #1
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    Unreachable code in function main()

    I just started programming, and I followed a tutorial to make a calculator. Once I was done, I wanted to make it more advanced, so it wouldn't crash if I try to divide by 0, but instead not giving me the choice of dividing. I thought I was done, but then it simply just skipped the part where it actually shows the result. I tried to fix it, but now I get the calculator.cpp 58: Unreachable code in function main() error.
    This is my code. Anyone who can solve the problem? Okay, it seems that it works anyway, and that it is just a warning when I compile. It does not stop it from compiling.
    Code:
    #include <stdio.h>
    #include <iostream.h>
    
    int main()
    {
    
      float num1;
      float num2;
      int num3;
      float num4;
    
      cout << "Enter a number." << endl;
      cin >> num1;
    
      cout << "Enter a second number." << endl;
      cin >> num2;
      
      if (num1 == 0 || num2 == 0)
      {
        {
        cout << "Choose an operation." << endl;
        cout << "Type 1 to add, 2 to subtract or 3 to multiply." << endl;
        cin >> num3;
        }
      
        if (num3 >3 || num3 <1)
        {
          cout << "You operation choice isn't valid! Please run the program again." << endl;
          cout << "Press Enter to end the proogram." << endl;
          getchar();
          return 0;
        }
        else
        {
          if (num3 == 1)
          {
            num4 = num1 +  num2;
            cout << "Result is: "<< num4<< endl;
          }
          else if (num3 == 2)
          {
            num4 = num1 - num2;
            cout << "Result is: "<< num4<< endl;
          }
          else if (num3 == 3)
          {
            num4 = num1 * num2;
            cout << "Result is: "<< num4<< endl;
          }
    
        }
      }
    
      cout << "Press Enter to end the program." << endl;
      getchar();
      return 0;
    
      if (num1 != 0 || num2 !=0)
      {
        {
        cout << "Choose an operation." << endl;
        cout << "Type 1 to add, 2 to subtract, 3 to multiply or 4 to divide." << endl;
        cin >> num3;
        }
    
        if (num3 >4 || num3 <1)
        {
          cout << "You operation choice isn't valid! Please run the program again." << endl;
          cout << "Press Enter to end the proogram." << endl;
          getchar();
          return 0;
        }
      }
      else
      {
        if (num3 == 1)
        {
          num4 = num1 +  num2;
          cout << "Result is: "<< num4<< endl;
        }
        else if (num3 == 2)
        {
          num4 = num1 - num2;
          cout << "Result is: "<< num4<< endl;
        }
        else if (num3 == 3)
        {
          num4 = num1 * num2;
          cout << "Result is: "<< num4<< endl;
        }
        else if (num3 == 4)
        {
          num4 = num1 / num2;
          cout << "Result is: "<< num4<< endl;
        }
    
      }
    
      cout << "Press Enter to end the program." << endl;
      getchar();
    
      return 0;
    }
    Last edited by DavidSS; 10-24-2010 at 07:59 AM. Reason: Found a solution.

  2. #2
    C++ Witch laserlight's Avatar
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    You have a premature return 0; in your main function, presumably a by-product of careless copying and pasting.
    C + C++ Compiler: MinGW port of GCC
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    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  3. #3
    a_capitalist_story
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    Last edited by DavidSS; Today at 08:59 AM. Reason: Found a solution.
    Yeah, I'm guessing in this cross-post?

    Cross-posting is highly frowned upon and shows a lack of consideration on your part for the time spent by people willing to help you for free.

  4. #4
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    Quote Originally Posted by rags_to_riches View Post
    Yeah, I'm guessing in this cross-post?

    Cross-posting is highly frowned upon and shows a lack of consideration on your part for the time spent by people willing to help you for free.
    Yes and no. Yes I did ask on three forums, because I know from past experience, that I am likely not to get the answer I am looking for on just a single forum, so I posted on three forums, because I really want to find a solution to my problem.
    Then no part, is because I found out my self, that the message was just a warning and not an error, so it did not stop the compiling.

  5. #5
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by DavidSS
    Yes I did ask on three forums, because I know from past experience, that I am likely not to get the answer I am looking for on just a single forum, so I posted on three forums, because I really want to find a solution to my problem.
    Be patient: ask on one forum, and if after some reasonable length of time you do not get an answer, ask on another forum, while keeping both forums informed of the duplication.

    Quote Originally Posted by DavidSS
    Then no part, is because I found out my self, that the message was just a warning and not an error, so it did not stop the compiling.
    In this case, the warning is legitimate and useful: it tells you that you have this part of your code that will not be executed, regardless of the input. Control cannot reach it, hence it is unreachable.
    C + C++ Compiler: MinGW port of GCC
    Version Control System: Bazaar

    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  6. #6
    a_capitalist_story
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    Quote Originally Posted by DavidSS View Post
    Yes and no. Yes I did ask on three forums, because I know from past experience, that I am likely not to get the answer I am looking for on just a single forum, so I posted on three forums, because I really want to find a solution to my problem.
    Then no part, is because I found out my self, that the message was just a warning and not an error, so it did not stop the compiling.
    Right. You got an answer in both places within 20 minutes ON A WEEKEND. Please don't try to justify your inconsiderate behavior.

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