If, else in a function?

So I am trying to do a simple subtraction problem where the larger number would go first so the difference can be a positive or zero, but I am stump. If I just remove the if and else with either x - y or y - x it would work. It is something in my function from what it seems.

Code:

---

#include <iostream>

using namespace std;

int sub ( int x, int y );

int main()
{
  int x;
  int y;

        cout<<"We will subtract two numbers and it will always be positive or zero.";
        cin.ignore();
        cout<<"Please input two numbers: ";
        cin>> x >> y;
        cin.ignore();
        cout<<"The difference is "<< sub ( x, y ) <<"\n";
        cin.get();
}

int sub ( int x, int y )
{
        if ( x < y ) {
                return y - x;
        }
        else ( x > y ) {
                return x - y;
        }
}

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Else should not have a condition. Just write else, followed by the curly brace.

It's either
else if (condition)
Or
else

Quote:

---

Code:

---

int sub ( int x, int y )
{
        if ( x < y ) {
                return y - x;
        }
        else ( x > y ) {
                return x - y;
        }
}

---

---

Or just replace "else" with "if".

No, that's not good, because this is a if or else if type of logic.

Thanks guys, else if works, but I did it before and it didn't work. I must have missed a semi colon before.

What about the case where neither if condition is met (for example, if I input 5 and 5)?

Don't forget to come up with a solution for that (hopefully you can figure it out before somebody gives it to you).


>> No, that's not good, because this is a if or else if type of logic.
Since the blocks contain a return statement, audinue's suggestion is logically equivalent to an if/else if. Whether it's better or worse for readability is probably a debate for another thread.

>> What about the case where neither if condition is met (for example, if I input 5 and 5)?

I did this, seems to work, I don't know if there is any way around it.

Code:

---

int sub ( int x, int y )
{
        if ( x < y ) {
                return y - x;
        }
        else if ( x > y ) {
                return x - y;
        }

        else  {
                return 0;
        }

}

---

http://www.mediafire.com/?myynmdyqmmz

>> I don't know if there is any way around it.
There are other ways, but that's just fine.

Quote:

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Originally Posted by Daved

>> No, that's not good, because this is a if or else if type of logic.
Since the blocks contain a return statement, audinue's suggestion is logically equivalent to an if/else if. Whether it's better or worse for readability is probably a debate for another thread.

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I know it is and in this case it might be fine, but in others it might not, since in if, all ifs are executed and checked, but in else/if, only the if/else ifs down to the point where the condition is true is evaluated.
Therefore, I suggest separating if and else if logic.

Quote:

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What about the case where neither if condition is met (for example, if I input 5 and 5)?

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Wouldn't this be handled automatically if you didn't check for the second condition (if x is not smaller than y, then it is greater or equal)?

Code:

---

if (x < y) {
    return y - x;
}
else {
    return x - y;
}

---

Quote:

---

Wouldn't this be handled automatically if you didn't check for the second condition (if x is not smaller than y, then it is greater or equal)?

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No actually, it comes out 5 instead of 0.

Quote:

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Originally Posted by ShinobiRAGE

No actually, it comes out 5 instead of 0.

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There must be some error in your code then, because it should definitely return 0;

For example -

Code:

---

if (x < y) {
    return y - x;
}
else {
    return x - y;
}

---

Lets plug in 5 and see,

Code:

---

if (5 < 5) {//False so skip
    return y - x;
}
else {//True
    return 5 - 5;//should be 0
}

---

also

Code:

---

int sub ( int x, int y )
{
        if ( x < y ) {
                return y - x;
        }
        return x - y;
}

---

>> Wouldn't this be handled automatically if you didn't check for the second condition?

Yes, and that's how I would do it (or even something closer to ಠ_ಠ's solution). But I think the solution ShinobiRAGE came up with is fine and it is at least original.