Thread: Need help making a program that prints a triangle of symbols in a certain direction

So I need to make a program that prints a triangle of symbols in a certain direction.
For example:

Code:

How many rows? 3

  @
 @@@
@@@@@

but I can't figure out how to do that. It's rare that I post without figuring anything out, but I'm just simply not sure. I have a program that prints a triangle in a similar direction, so maybe if I could get some hints as to what to do with that (HINTS, not direct source code) it would help.
My code:

Code:

#include <iostream>
#include <iomanip>
using namespace std;
int main ( ) {
    int rows;
    cout << "How many rows? ";
    cin >> rows;
    rows = rows + 1;
    cout << endl;
    for(int r = 0; r < rows; r++) {
            for(int c = 0; c < r; c++) {
                    cout << "@";
                    }
                    cout << endl;
                    }
                    }

Can anyone help?

Okay, here's another hint. Notice how the middle column index is 2? (This makes sense as the possible indices are 0, 1, 2, 3, 4)

Well, when you're assigning, you can use that to your advantage. For row 0, array[0][2] = @.

For row 1, array[1][1], array[1][2], array[1][3] are @.

For row 2, array[2][0 - 4] are @.

You can write a for-loop to assign values in both directions using the row number.

What I want you to see is that 2 - 1 = 1 and 2 + 1 = 3.

2 - 2 = 0, 2 - 1 = 1 and 2 + 1 = 3 and 2 + 2 = 4.

Originally Posted by MutantJohn

Well, you know the maximum number of @'s is dependent upon the number of rows. You go from 1 to 3 to 5.

You have 5 maximum indices. You know for 0, only index 2 gets printed. For row 1, indices 1, 2, 3 get printed. For row 2, all 5 indices get printed.

So just figure out when you should print @ for an index in a row and a blank space.

Basically, imagine a 3x5 array. Some elements of the array are @ and other elements are blank spaces. Assign the proper values to the array and then it will print properly.

OK, I need it to print @ after a certain number of spaces depending on row, but how do I do that?