Use function declared below current function (allow circular dependency)?

Question

So C++ won't let me use a function physically above where I declare it (in other words, the function must be on a smaller line number than its use). My problem is my functions all depend on at least one of the others. In other words:

void funct1()
{
     if (something is true)
     {
         funct2();
     }
     else
          cout << someResult;
}


void funct2()
{
     if(something is true)
     {
         funct3();
     }
     else
          cout << someResult;
}

void funct3()
{
     if (something is true)
     {
         funct1();
     }
     else
          cout << someResult;
}
}

In other words, each function needs to call one of the others in some cases. This will not work regardless of what order I put the functions in because at least one depends on something below it. How do I make the compiler look below the current function when compiling (i.e. read everything then decide what is valid) I am using g++ on CodeBlocks.

If all functions depend on each other, that's usually an indication of a design flaw, but there are forward declarations. — chris, Mar 25 '13 at 22:43
You need to forward declare funct1 and funct3 => http://www.learncpp.com/cpp-tutorial/17-forward-declarations/ — user2184879, Mar 25 '13 at 22:45
Also, look @ http://stackoverflow.com/questions/4757565/c-forward-declaration for a great overview. — user2184879, Mar 25 '13 at 22:51

score 2 · Accepted Answer · answered Mar 25 '13 at 22:43

2

Add some forward declarations before the function definitions:

void funct1();
void funct2();
void funct3();

This way, you can use the functions in any order.

answered Mar 25 '13 at 22:43

mfontanini

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score 0 · Answer 2 · answered Mar 25 '13 at 22:44

I'm presuming you meant for the last function to be funct3. You can get away with using a single forward declaration:

void funct2();

void funct1() { if(something is true) { funct2(); } else cout << someResult; }

void funct3() { if(something is true) { funct1(); } else cout << someResult; }

void funct2() { if(something is true) { funct3(); } else cout << someResult; }

It just completes the cycle. funct2 <- funct1 <- funct3 <- funct2.

However, I'm highly suspicious of any code that has dependencies like this.

thanks, the reason for the dependencies is that I am creating a cascading loop of actions (one thing causes the next, some of which start another chain off) — user2209501, Mar 25 '13 at 23:10

Use function declared below current function (allow circular dependency)?

2 Answers2