WAP in C++ to print the pattern

Question

1
23
456
and the pattern
1
12
123
1234

Answer 1

Treating this like a practice once in a while.

int i = 1;

for (int j = 1; j <= 3; j++, cout << "\n")
{
for (int k = 0; k < j; k++) cout << i++;
}

//and

for (int i = 1; i <= 4; i++)
{
for (int j = 1; j <= i; j++)
{
cout << j;
}
cout << endl;
}

Answer 2

can u please explain the working ??