Number pattern in C++ - c++

Question

I want to print a number pattern:
1
2 4
3 6 9
4 8 12 16
5 10 15 20 25
...
10 . .. . .
This is my code:
#include <iostream>
#include <conio.h>
using namespace std;
int main()
{
int cols, row, num=1;
for(row=1; row<=10; row++)
{
for(cols = row; cols <= row*10; cols = cols + row)
{
cout << cols << " ";
}
cout << "\n";
}
return 0;
getch();
}
But it gives me the output:
1 2 3 4 5 6 7 8 9 10
2 4 6 8 10 12 14 16 18 20
3 6 9 12 15 18 21 24 27 30
4 8 12 16 20 24 28 32 36 40
5 10 15 20 25 30 35 40 45 50
6 12 18 24 30 36 42 48 54 60
7 14 21 28 35 42 49 56 63 70
8 16 24 32 40 48 56 64 72 80
9 18 27 36 45 54 63 72 81 90
10 20 30 40 50 60 70 80 90 100

Answer 1

To make that pattern you only really need the number of rows. The number of columns in each row happens to be equal to the row number, and the values are integer-multipliers of that row number.
#include <iostream>
int main()
{
const int rows = 10;
for (int row = 1; row <= rows; ++row)
{
for (int col = 1; col <= row; ++col)
{
int value = row * col;
std::cout << value << ' ';
}
std::cout << '\n';
}
}
Output
1
2 4
3 6 9
4 8 12 16
5 10 15 20 25
6 12 18 24 30 36
7 14 21 28 35 42 49
8 16 24 32 40 48 56 64
9 18 27 36 45 54 63 72 81
10 20 30 40 50 60 70 80 90 100