Errors that make no sense...

Everything I touch in programming gets ruined. Errors all over the place.
It's another group project, but this time we have to present it to the class and it refuses to compile. We don't even understand the errors. The program is supposed to return the distance between two input coordinates.
Here's what we have so far:

Code:

---

#include <iostream>
#include <stdlib.h>
#include <math.h>

using namespace std;
int GetCoordinate ();
double GetDistance (double X1, double Y1, double X2, double Y2);
void PrintResults (/*double d, double X1, double Y1, double X2, double Y2*/);

int main(int argc, char *argv[])
{
  double X1=0;
  double Y1=0;
  double X2=0;
  double Y2=0;
  double d;
  GetCoordinate();
  d = GetDistance (double X1, double Y1, double X2, double Y2);
  PrintResults();
system ("PAUSE");
  return 0;
} 

int GetCoordinate ();
    {
        cout << "Enter the coordinates of two points (X1,X2),(Y1,Y2)" << endl;
        cin >>X1>>X2>>Y1>>Y2;
    }
   
    double GetDistance /*(double X1, double Y1, double X2, double Y2, double d)*/;
    {
        double d = sqrt(pow((Y2-Y1), 2.0) + pow((X2-X1), 2.0));
    }
   
    void PrintResults (double d, int X1, int Y1, int X2, int Y2);
    {
        cout << "The distance between ("<<X1<<", "<<X2<<") and" << endl;
        cout<< "("<<Y1<<", "<<Y2<<") is "<<d<<"." << endl;
    }

---

Here is our collection of errors that we cannot sort out.

• N:\distancecode.cpp In function `int main(int, char**)':
• 18 N:\distancecode.cpp syntax error before `,' token
• distancecode.cpp N:\distancecode.cpp At global scope:
• 25 N:\distancecode.cpp syntax error before `{' token
• 27 N:\distancecode.cpp syntax error before `>>' token
• 30 N:\distancecode.cpp `double GetDistance' redeclared as different kind of symbol
• 7 N:\distancecode.cpp previous declaration of `double GetDistance(double, double, double, double)'
• 31 N:\distancecode.cpp syntax error before `{' token
• 36 N:\distancecode.cpp syntax error before `{' token
• 38 N:\distancecode.cpp syntax error before `<<' token
• [Linker error] undefined reference to `GetDistance(double, double, double, double)'

Maybe these are really easy to fix but we're too inexperienced to figure out what to do. If someone would please shed some light on these errors we'd be much obliged.

18 N:\distancecode.cpp syntax error before `,' token

Don't need to include data types when calling a function, hence no 'double's


Also, don't put a semicolon at the end of the function name when you are defining it. and don't comment out the parameter list.

Start with this:

Code:

---

double GetDistance /*(double X1, double Y1, double X2, double Y2, double d)*/;

---

Format in C++ is very specific and it must be exact. You cannot define a function like this:

double SomeFunc;

A function definition looks like this:

Code:

---

double SomeFunc(double p1, double p2)
{
      //lines of code
}

---

If you are that inexperienced, I suggest that C++ is not the language you should be using for your project.

Several errors that I see, one thats common and one that really confuses me. The common error is that you have semicolons after your function definitions, the ones after main, not before. Basically when you put the semicolons there you are saying your definition is done thus they aren't getting defined and the compiler views the code in the braces as extraneous.

The second error which I don't understand is where you comment out the variables in PrintResults before main and in GetDistance after main. Take out the /* and the */ as well as the semicolons I mentioned above, recompile and let us know what the new results are.

[edit] doh, beaten not once, but twice lol [/edit]

We wouldn't do the project in C++ except it's a C++ class.
Originally the school advertised it as being a class in BASIC, but the teacher decided he liked this language better despite all of us learning nearly nothing.

Also, a couple of other errors that I know you'll have problems with after you fix the above mentioned ones. Notice how your function declarations above main do not match exactly with the error definitions after main? For example, GetDistance is declared at first as having 4 paramaters, but when you define it later you put in an extra parameter called double d. Also, for PrintResults you declare all parameters as ints but later on then at the bottom you change to double. When you declare a function, it must match exactly with how you define it later on, otherwise the compiler will view these as two different functions.

Also, a couple of your functions are listed as returning variables, yet you don't return anything.

Here is what the format of a function should look like:

Code:

---

#include <iostream>
using namespace std;

//function 'declaration'
double My_func(double d1, double d2);

int main()
{

        double x1 = 10.0;
        double x2 = 3.5;

        double answer = My_func(x1, x2); 

        cout<<answer<<endl;

        return 0;
}

//function 'definition':
double My_func(double d1, double d2)
{
        double result = d1 + d2;
        return result;
}

---

You also might want to read this one page tutorial on functions:

http://www.cprogramming.com/tutorial/lesson4.html

New set of errors includes:
N:\distancecode.cpp In function `int GetCoordinate()':
7 N:\distancecode.cpp syntax error before `double'
N:\distancecode.cpp In function `double GetDistance(double, double, double, double)':
8 N:\distancecode.cpp syntax error before `void'
N:\distancecode.cpp In function `void PrintResults(double, double, double, double, double)':
10 N:\distancecode.cpp syntax error before `int'
N:\distancecode.cpp In function `int main(int, char**)':
10 N:\distancecode.cpp too few arguments to function `void PrintResults(double, double, double, double, double)'
19 N:\distancecode.cpp at this point in file
25 N:\distancecode.cpp syntax error before `{' token
27 N:\distancecode.cpp syntax error before `>>' token
30 N:\distancecode.cpp `double GetDistance' redeclared as different kind of symbol
8 N:\distancecode.cpp previous declaration of `double GetDistance(double, double, double, double)'
30 N:\distancecode.cpp confused by earlier errors, bailing out (This is my favorite)
[Linker error] undefined reference to `GetDistance(double, double, double, double)'

Even the compiler gave up on this...

You'll need to repost the new code.

A major point... (beyond the function not returning a value as you indicate it should and the extra ';' after the function):

Code:

---

int GetCoordinate ();

int main(int argc, char *argv[])
{
    double X1=0;
    double Y1=0;
    double X2=0;
    double Y2=0;

    GetCoordinate();

    ...

} 

int GetCoordinate ()
{
    cout << "Enter the coordinates of two points (X1,X2),(Y1,Y2)" << endl;
    cin >>X1>>X2>>Y1>>Y2;
}

---

The variables in blue above are local to the function main. They have no scope (they don't exist) beyond that function. Your GetCoordinate function attempts to store information into the variables in red which do not exist in that function. For this to work you would either need to make the variables X1, X2, Y1, and Y2 global or you would need to pass them into the GetCoordinate function (pass-by-pointer or pass-by-reference) from main.

Updated code:

Code:

---

using namespace std;
int GetCoordinate ()
double GetDistance (double X1, double Y1, double X2, double Y2, double d)
void PrintResults (double d, double X1, double Y1, double X2, double Y2)

int main(int argc, char *argv[])
{
  double X1;
  double Y1;
  double X2;
  double Y2;
  double d;
  GetCoordinate();
  d = GetDistance ( X1, Y1, X2, Y2);
  PrintResults();
system ("PAUSE");
  return 0;
} 

int GetCoordinate ();
    {
        cout << "Enter the coordinates of two points (X1,X2),(Y1,Y2)" << endl;
        cin >>X1>>X2>>Y1>>Y2;
    }
   
    double GetDistance (double X1, double Y1, double X2, double Y2, double d)*/;
    {
        double d = sqrt(pow((Y2-Y1), 2.0) + pow((X2-X1), 2.0));
    }
   
    void PrintResults (double d, int X1, int Y1, int X2, int Y2);
    {
        cout << "The distance between ("<<X1<<", "<<X2<<") and" << endl;
        cout<< "("<<Y1<<", "<<Y2<<") is "<<d<<"." << endl;
    }

---

And here's our collection of errors:

• 7 C:\My Documents\Zoraa stuff\distancecode.cpp syntax error before ` double'
• C:\My Documents\Zoraa stuff\distancecode.cpp In function `double GetDistance(double, double, double, double, double)':
• 8 C:\My Documents\Zoraa stuff\distancecode.cpp syntax error before ` void'
• C:\My Documents\Zoraa stuff\distancecode.cpp In function `void PrintResults(double, double, double, double, double)':
• 10 C:\My Documents\Zoraa stuff\distancecode.cpp syntax error before ` int'
• C:\My Documents\Zoraa stuff\distancecode.cpp In function `int main(int, char**)':
• 18 C:\My Documents\Zoraa stuff\distancecode.cpp cannot convert `double* ' to `double' for argument `1' to `double GetDistance(double, double,
• 10 C:\My Documents\Zoraa stuff\distancecode.cpp too few arguments to function `void PrintResults(double, double, double, double, double)'
• 19 C:\My Documents\Zoraa stuff\distancecode.cpp at this point in file
• 25 C:\My Documents\Zoraa stuff\distancecode.cpp syntax error before `{' token
• 27 C:\My Documents\Zoraa stuff\distancecode.cpp syntax error before `>> ' token
• C:\My Documents\Zoraa stuff\distancecode.cpp In function `double GetDistance(double, double, double, double, double)':
• 10 C:\My Documents\Zoraa stuff\distancecode.cpp too few arguments to function `void PrintResults(double, double, double, double, double)'
• 19 C:\My Documents\Zoraa stuff\distancecode.cpp at this point in file
• 25 C:\My Documents\Zoraa stuff\distancecode.cpp syntax error before `{' token
• 27 C:\My Documents\Zoraa stuff\distancecode.cpp syntax error before `>> ' token
• C:\My Documents\Zoraa stuff\distancecode.cpp In function `double GetDistance(double, double, double, double, double)':
• 30 C:\My Documents\Zoraa stuff\distancecode.cpp redefinition of `double GetDistance(double, double, double, double, double)'
• 8 C:\My Documents\Zoraa stuff\distancecode.cpp `double GetDistance(double, double, double, double, double)' previously defined here
• 30 C:\My Documents\Zoraa stuff\distancecode.cpp redefinition of `double GetDistance(double, double, double, double, double)'
• 8 C:\My Documents\Zoraa stuff\distancecode.cpp `double GetDistance(double, double, double, double, double)' previously defined here
• 30 C:\My Documents\Zoraa stuff\distancecode.cpp syntax error before `*' token
• 36 C:\My Documents\Zoraa stuff\distancecode.cpp syntax error before `{' token
• 38 C:\My Documents\Zoraa stuff\distancecode.cpp syntax error before `<< ' token

Sorry if there's any repeated errors.

And if someone could remind me how to pass-by-reference I'd be much obliged. All I remember is something about an ampersand...

Quote:

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And if someone could remind me how to pass-by-reference I'd be much obliged. All I remember is something about an ampersand...

---

A pointer is just a variable that holds a memory address, and placing an ampersand before a variable name just uses the address of that variable. So you can pass &variable to a function that expects a pointer. It's a bit like "pointer literals".

I have a better idea--don't pass pointers or references. In fact, don't pass anything. Forget about calling a function to get the data, and do it in main() instead.

Quote:

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And if someone could remind me how to pass-by-reference I'd be much obliged. All I remember is something about an ampersand...

---

That's all it takes--you just use an ampersand after the type, e.g.:

(double& p1, double& p2)

What you really need to do is to get one function to work. I suggest you write a little practice program that sends one value to a function, and then the function doubles the value and returns it, and then in main() you display the value. Once you get a function like that to work, you'll have a better idea of how to proceed with all the errors you have. The general idea in programming is to write one function at a time and test the function until you get it to work. Then, you write another function and test it. You don't write several functions and then run your program when you are all done. So, I suggest you start over, and write one function at a time, and get everything to work before adding functions.

Anything's worth a try.
Hope Heather's not too offended that we chucked her code and started over. It would help if she showed up to class once in a while though.
Thanks guys.
Although for future reference, I always seem to get errors like "Syntax error before <<" when I can't see anything wrong. Any suggestions?

For the Syntax errors you might have spelled something wrong, or forgot a character. I do that a lot of the time.

You last post did not have the proper include:

#include <iostream>

so be sure to always check that the proper includes are at the top of the file.

Read this when you're no longer in frustration-mode... or is it panic-mode? :) Maybe after you get your program working.

Develop your code a few lines at a time.

Someday I'm going to write an essay on this topic. It seems like a lot of instructors don't really teach how to approach a programming problem. This result in lots of frustrated beginners & students. Nobody... not even experienced programmers write the whole program before trying it out!

1- Start-out with a 'Hello World" type program. You can substitute "Hello World" with some better descriptiion of the program. :)

2- Add one or two lines of code at a time. Compile, test-run, and debug before adding more lines.

3- Add some extra cout statements so you can "see" what the program is doing, and confirm that it's working so-far. (You can take them out, or coment them out later.)

4- When you create a function, make an empty (do-nothing) function first. Make the function prototype, the empty function definition, and the function call. Then, test-compile. If your function needs to return a value, just make it return a constant (i.e. return 10; ). It's also helpful to put a cout statement in your do-nothing function, like: cout << "In GetDistance() function \n"; .

Now, this isn't as easy as it sounds, because you can't just write line one, then line two, then line three, of your code. (It won't compile if you do that.) The trick (the fun part, actually) is figuring-out which part of the code makes sense to develop next.

Compilers can easily get confused when there's an error (or two). Sometimes they will point to the wrong line. Sometimes one error will cause the compiler to report several errors. Link errors are even trickier to track-down.

So, it really helps to test-run and test-compile after every one or two lines. As you gain experience, you can write whole functions before testing. But, as you gain experience your programs generally will get longer and more complex, so you still won't be writing the whole program before testing & debugging.

I once had a misplaced bracket (after a cut-and-past), and the comipler reported over one hundred errors! ... from one tiny little misplaced bracket! :D

Dear lord, over 100 errors from a missing bracket?
You think debugging the code is the fun part?
Whoa.

I was bored and saw this thread, here is how I would have done it:

Code:

---

#include <iostream>
#include <stdlib.h>
#include <math.h>

using namespace std;
   
double GetDistance(double X1, double Y1, double X2, double Y2) {
        double d = sqrt(pow((Y2-Y1), 2.0) + pow((X2-X1), 2.0));
        return d;
}

int main()
{
  double X1, Y1, X2, Y2, result;

  cout << "Enter the coordinates of two points (X1,X2),(Y1,Y2)" << endl;
  cin >> X1 >> X2 >> Y1 >> Y2;

  result = GetDistance(X1, Y1, X2, Y2);


  cout << "The distance between (" << X1 << ", " << X2 <<
          ") and (" << Y1 << ", " << Y2 << ") is " << result << "." << endl;

  system ("PAUSE");
  return 0;
}

---

no need for extra functions when you dont have to!
Dag

Quote:

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I was bored and saw this thread, here is how I would have done it:

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Please familiarize yourself with the cboard homework policy:

http://cboard.cprogramming.com/annou...ouncementid=39

Okay, I thought that was just if the person were asking others to do his homework.... Not if someone just wants to write the code. I think that is a good way to learn(for me or the person who try to write it)-- by sharing code, getting comments back.
Sorry if I did wrong.

Thanks again to everyone who helped us out. One less major source of stress to deal with.

Quote:

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Okay, I thought that was just if the person were asking others to do his homework.... Not if someone just wants to write the code.

---

:confused: