4 replies to this topic

[CollegeProginTraining]

I am getting a compiler error code C2440 when I try to build this program.
Any help is appreciated.

/* Euclidean.cpp


	Writing the Euclidean algorithm using C++.



10-29-06

Lab 7

*/


#include<iostream>

using namespace std;


int gcd( int & a, int & b, int & c);

int main(){

	int a, b, c;

	cout << "Enter the first number: ";

	cin >> a;

	cout << "Enter the second number: ";

	cin >> b;

	return gcd;

}

int gcd( int & a, int & b, int & c){

	if (b = 0){

		b = a;

	}

	else{

		a = b;

		c = a % b;

		b = c;

	}

	return a/c;

}



Output results:

1>------ Build started: Project: Lab7, Configuration: Debug Win32 ------

1>Compiling...

1>Euclidean.cpp

1>c:\comp128\lab7\lab7\euclidean.cpp(20) : error C2440: 'return' : cannot convert from 'int (__cdecl *)(int &,int &,int &)' to 'int'

1>        There is no context in which this conversion is possible

1>Build log was saved at "file://c:\Comp128\Lab7\Lab7\Debug\BuildLog.htm"

1>Lab7 - 1 error(s), 0 warning(s)

========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

[monjardin]

You are attempting to return the address of your gcd function. Replace the line "return gcd;" with "return gcd(a, b, c);".

Try reading up on variable scoping and function calls. GIYF

[pater]

BTW: You should not pass the arguments by reference to your gcd function. In this simple program, you're not using the variables after the call, so it doesn't matter, but as soon as you'll be doing anything more complicated, you'll get wrong results on any further computation.
Replace int gcd(int &a, int &b, int &c) by int gcd(int a, int b) both times. C is only used as local var, so it hasn't got anything to do in the method header. Declare it locally.
Besides, I doubt your algorithm is correct. There must be some loop or recursion in there. And "=" is not a comparison operator.

[Kenneth Gorking]

Also, c is never initialized in main. If the user passes 0 as b, you get a division with an uninitialized variable, and then you're screwed. But on the other hand, if the user doesn't pass 0 to b then you will get a division by zero, in which case you are also screwed. :)

[dega512]

Watch out, right now you are returning whatever gcf returns as an error code when you exit the program.