What does i(row) and j(col) mean?

Question

Okay so I'm trying to understand what the int i(row) and the j(col) means in this set of code, does it set i to the value in row?

for( int i(row); i < row + height; ++i )
{
    // Cycle through cols
    for( int j(col); j < col + width; ++j )
    {
        // Change the value at position ( i, j ) to the fillChar
        board[i][j] = fillChar;
    }
}

Yes, exactly. `int` also has a default constructor: `int i{}; // i is 0`. — Brian Rodriguez, Jul 17 '17 at 23:10
Yes you could. I would say that would improve the readability of the code. — drescherjm, Jul 17 '17 at 23:14
@user0042 That's why I was careful to say "think of it as a constructor". — Brian Rodriguez, Jul 17 '17 at 23:18

score 1 · Answer 1 · answered Jul 17 '17 at 23:14

non-class/struct types in C++ (such the intrinsic/"primitive" types int, long, etc) do not have constructors, but they do have an initialization syntax which looks the same as a constructor call.

As an example, calling a class-type's constructor looks like this:

my_class myClassInstance( myClassConstructorArgument );

Similarly, using int's initializer looks like this:

int myInt( myInitialValue );

So in your case, for( int i(row); ... is the same as for( int i = row; ....

There is a third syntax that uses curly braces too:

int x = 1;
int y(2);
int z{3};

cout << x << " " << y << " " << z << endl;

gives the output 1 2 3.

What does i(row) and j(col) mean?

1 Answers1