C++ Value Return Function that produces a true/false

[zamaam0728]

I am at the end of my first semester of C++, and I'm not sure what I should do to make this program meet the requested specifications. The assignment is as follows:

Write a function called ignoreCaseCompa re() that has two character (char) parameters. The function should return true if the two characters received represent the same letter, even if the case does not agree. Otherwise, the function should return false. Then, write a simple main() function that uses your ignoreCaseCompa re().

Additional instructions:

Here is the function heading:
bool ignoreCaseCompa re(char c1, char c2)

{

//Write the code to compare c1 with c2 and return true/false

}


Here is what I have:

#include <iostream>
 
using std::cout;
using std::cin;
using std::endl;
 
//function prototype
bool ignoreCaseCompare (char first, char second);
 
int main ()
{
    char first = ' ';
    char second = ' ';
 
    cout << "Enter a letter: ";
    cin >> first;
    cout << "Enter another letter: ";
    cin >> second;
 
    first = toupper(first);
    second = toupper(second);
 
    cout << "Are the letters the same? " <<
 
    return 0;
}
//******function defintions*****
bool ignoreCaseCompare (char one, char two)
 
{if (one == two)
return true;
else
return false;
}
 
    //end main function

This programs is much easier without the value-return function. Can anyone offer any advice or direction?

[Frinavale]

If a function returns void then it doesn't return anything!

In your case your function should return a bool (true or false), so your function can't be void. Unless you're talking about the main function....tha t one could return void.

-Frinny

[zamaam0728]

Ok...I got it to go through with no error messages, but it's not displaying true or false.

#include <iostream>
 
using std::cout;
using std::cin;
using std::endl;
 
//function prototype
bool ignoreCaseCompare (char, char);
 
int main ()
{
    char first = ' ';
    char second = ' ';
    char answer = ' ';
 
    cout << "Enter a letter: ";
    cin >> first;
    cout << "Enter a letter: ";
    cin >> second;
 
    answer = ignoreCaseCompare (first, second);
    cout << "The letters are the same: " << answer << endl;
 
    return 0;
}
//******function definitions**********
bool ignoreCaseCompare (char one, char two)
{
    one = toupper(one);
    two = toupper(two);
 
    if (one == two)
        return true;
    else
        return false;
}
//end main function

[zamaam0728]

Thank you for all of your help. You helped me see the obvious mistakes, and explained the errors to me so I won't make the same mistakes again.

[zamaam0728]

It may not be pretty but here it is:

#include <iostream>
 
using std::cout;
using std::cin;
using std::endl;
 
//function prototype
bool ignoreCaseCompare (char, char);
 
int main ()
{
    char first = ' ';
    char second = ' ';
    char answer = ' ';
 
    cout << "Enter a letter: ";
    cin >> first;
    cout << "Enter a letter: ";
    cin >> second;
 
    cout << "The letters are the same: ";
    answer = ignoreCaseCompare (first, second);
    cout << endl;
 
    return 0;
}
//******function definitions**********
bool ignoreCaseCompare (char one, char two)
{
    one = toupper(one);
    two = toupper(two);
 
 
    if (one == two)
        cout << "true";
    else
        cout << "false";
    return 0;
}
//end main function

[Frinavale]

I'm glad you were finally able to compile your project.


Whenever you are posting code for us to take a look at could you please use code tags? It makes it a lot easier for us to read your code and it gives us line numbers that help when we are trying to refer to a specific line of code.

Your ignoreCaseCompa re function returns a type bool....see your function's signature:

bool ignoreCaseCompare (char one, char two)

Notice how you have "bool" in front of the function name?
This is the type that the function should be returning.

Now, take a look at the last line in your function:

return 0;

You are returning an int (0)....this is not a boolean value.
You should be returning true or false depending on whether or not the characters matched.

You could approach this a couple of ways but I think the best practice is to have 1 return for the function (just like what you're doing)....you are going to need to have a bool variable within your ignoreCaseCompa re method that will keep track of whether or not the character is the same. You will return this bool at the end of the function.


Do you understand what I'm trying to say?

-Frinny

[zamaam0728]

Frinny,

Thanks for all of your help. I'm not sure if I understand the code tags. I did read the link.

If I understand you correctly, you are referring to the function, and the fact that it does not really serve its purpose.

I first attempted this:

if (one == two) 
      return true;
else
      return false;

But no answer appeared.

[newb16]

Because you output the result as '0' or '1' ( cout interprets bool in integer, apparently). Use something like cout << answer?"true":" false";

[Frinavale]

What you had originally is what is expected of the function.
The function is supposed to return a value...not print the value.

What I was recommending is that you only have 1 return statement in your function. This is "good coding practice" because gives your function 1 entry point and 1 exit point. It makes it easier to understand by humans and compilers.

I was recommending that you do this:

bool ignoreCaseCompare (char one, char two)
{
//declare a variable to keep track of what to return
bool isSameCharacter = false;
 
// set the variable according to whether or not  the characters match
    if (toupper(one)== toupper(two)){
       isSameCharacter = true;
    }else{
       isSameCharacter = false;
    }
 
//return whether or not the characters are the same
 
    return isSameCharacter;
}

Now, the reason the value is not being printed in this case is because the function is not supposed to print anything!

Your function is simply supposed check if it's the same character and then return true or false accordingly (right??)

It's not the responsibility of the ignoreCaseCompa re to print anything....you should do this in your main method.


In your main method on line 22, you are storing the result of the method into "answer" (I don't see where you've defined/declared this variable)...but you are not printing this variable onto the screen...you should have a cout that prints the answer onto the screen

See newb16's post (just above this one)!

:)

-Frinny

[Banfa]

Normally cout does interpret bool as an integer (it is implemented as one after all) but you can get text output like this

cout << boolalpha << answer;

where boolalpha is an iomanipiulator.

[Banfa]

Unless you're talking about the main function....tha t one could return void.

No, no, no absolutely never ever ever never ever never ever (getting the picture?) should main return void.

main returns int, returning void is at best an extension and unnecessairly making you code non-portable and at worst undefined behaviour.

Always return int from main.