CODEWITHSUNDEEP
c++
Jonathan Kuhl
Jonathan Kuhl

Reputation: 709

Using the same parameter in different functions

So I was curious about something. I have two functions, both work the way I want them to, and they are as follows:

//this function returns the absolute value of a number
int abs(int y) {
    if (y < 0) {
        return -1 * y;
    }
    return y;
}

//gives a random number, multiplied by x, in the range 1-y
int randomNum(int x, int y) {
    srand((int)time(0));
    return abs(x * rand() % y) + 1;
}

They both work, so their functionality is not the problem. But if you'll notice, they both use a parameter called "int y."

My question is, despite the fact that these two functions work, is this bad practice that might screw me over in more complex programs? Or does it not matter because the variables are local to their respective functions?

I mean, it's obviously no big deal if I change one of the "int y" parameters to something else, I'm just curious, is all.

Upvotes: 0

Views: 1174

Answers (2)

Soner from The Ottoman Empire
Soner from The Ottoman Empire

Reputation: 20931

I think it is okay for simple programs.

However, you should name a variable using the same care with which you name a first-born child.

Robert C. Martin, Clean Code: A Handbook of Agile Software Craftsmanship

For instance, nobody prefers to read the declaration int foo(int x, int y, int z, int xx, int bb, int cc .....)

Upvotes: 2

lu5er
lu5er

Reputation: 3564

Whenever there is a variable inside braces { }, it is local to the scope. Once out of the braces it simply dies.

Now the code that you are asking, 

// y is declared in abs and is alive only in the abs
int abs(int y) {
    if (y < 0) {
        return -1 * y;
    }
    return y;
}

// the previous y dies here and is inaccessible.

// a new instance of y is created in randomNum and it's valid till the brace ends
int randomNum(int x, int y) {
    srand((int)time(0));
    return abs(x * rand() % y) + 1;
}

Now a little thing to try out as pointed out by Jawad Le Wywadi

int main()
{
    int a = 0;
    ++a;
    {
        int a = 1;
        a = 42;
        cout << a;
    }
    cout << a;
}

Try it yourself and let us know what do you realize in the comments.

Upvotes: 0

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