the logic of equality operators

[LuckyShot]

Hello, i I'm a beginner in the arts of c++ and stumbled upon a little logical question while doing a practice program I designed myself about equations.

Don't know how to post the code as IDE-like code so if someone can enlighten me,
please do. (This have been corrected.)

At the first if equation if (a == b, a == c). I first wrote if (a == b, b == c)
The problem was that if the first entry was 100, and the 2 last was, say 50
it reported all 3 numbers to match.


I found the problem but don't know why this is correct and the other not.
The program is as follows.

#include <iostream>
using namespace std;

int main ()

{
	
	int a, b, c;	// Declares 3 integer variables.
	
	/* The program starting text */
	cout << "Enter 3 numbers and the program will check if they match." << endl;
	
	
	cout << "Enter a number: ";   // Promt for the first input.
	cin >> a;  
	
	
	cout << "Now enter another: "; // Second promt.
	cin >> b; 	
	
	
	cout << "Now for the final number: "; // Final promt.
	cin >> c;  
	
		
		if (a == b, a == c) // This one checks if all 3 input matches.
		
			cout << "All 3 numbers match."; 
		
		else if (a==b)	
		
			cout << "The first and second numbers match.";
		
		else if (a==c)
	
			cout << "The first and last mumbers match.";
		
		else if (b==c)
	
			cout << "The second and last numbers match.";
		
		else
	
			cout << "None of the numbers you entered match each other."; 
	
	return 0;
}

[Ispil]

Replace the comma in the if statement with &&. && is the AND logic operator, and checks first whether the left is true, and then whether the right is true. If they are both true, than it returns true.

[LuckyShot]

Ah, thanks for quick answer. I will replace it, you mean like this? (a == b && b == c)?

[Ispil]

That will work perfectly. Also, next time you post code, be sure to use the ['code][/code] tags, just so that it is easier to read (being sure to get rid of that apostrophe in the first half of the tag).

[LuckyShot]

Thanks, i corrected the code-tags now =)

Also, the program runs fine now even if I use if (a == b && b==c ) now =D