Make a character repeat in C++.

[PlainEsoteric]

Hello guys,

I would like your help with a basic thing, repeating characters.

For example the program should display:
1
22
333
4444.

I can use a for loop to make it display the first and the after the loop, I increment the value.

Then,execute a loop again, but this time it should give 1 more character than the previous one. This is the part I'm stuck with.

Please don't write the code if possible just explain and I'll write it otherwise I won't learn anything. If I get stuck I'll come back.

Thanks :)

[Peter87]

You could use the value that you increment, in the loop condition to decide how many times the loop should run.

[Chervil]

Ir sounds like a case where nested loops could be useful.

That is, put a for-loop contained within another for loop. The important part is how the inner loop can be made dependent on the variable which is controlling the outer loop.

[PlainEsoteric]

Thanks guys, I'll try it and post back. :)

[vlad from moscow]

I am showing the code because I doubt that you are able to write the same code.

#include <iostream>
#include <iomanip>

int main()
{	
	while ( true )
	{
		std::cout << "Enter a non-negative number (0 - exit): ";

		size_t n = 0;
		std::cin >> n;

		if ( !n ) break;

		std::cout << std::endl;

		for ( size_t i = 1; i <= n; i++ )
		{
			std::cout << std::setw( i + 1 ) << std::setfill( char( i % 10 + '0' ) ) << '\n';
		}

		std::cout << std::endl;
	}
}

[PlainEsoteric]

Thanks Vlad, indeed it would be impossible for me to write it like that for now. Here's a solution that I tried but I'm not sure myself why it works:

#include <iostream>
using namespace std;
int main() 
{
  for (int i = 1; i <= 5; ++i) 
  {
        for (int j = 0; j <= i; ++j) 
        {
             cout << i;
        }
        cout<<endl;
  }
}

How does it display 11, then 222, then 3333? When I wrote it I thought it would give me 1, 2 , 3 but it works and I don't know why it works.

[manudude03]

Change line 7 to either:
for (int j = 1; j <= i; ++j)
or:
for (int j = 0; j < i; ++j)

To give the first example in your code, when i=1, it prints 1 the first time, but because the second loop is still true on its second iteration (1<=1) it prints it a second time. Also, I don't think it makes a difference here, but most for loops I've seen use j++ rather than ++j.

[PlainEsoteric]

So, as long as the for-loop is true it will print it?

But how come it becomes 3333, 44444, 555555 later on, and not 33,44,55?

Thanks :)

[manudude03]

i is also increasing (in the first for loop), so for i=3, it would be true 4 times, 5 times for i=4 etc.

[MikeyBoy]

But how come it becomes 3333, 44444, 555555 later on, and not 33,44,55?

Think how many times your inner loop is going to iterate, depending on the value of i. That will explain it.

[PlainEsoteric]

Thanks guys :) I got it.