DaniWeb Forum Index > Software Development > C++

C++ RSS

Help w/ for loop.

Please support our C++ advertiser: Intel Parallel Studio Home

•

Join Date: Oct 2005

Posts: 11

Reputation: smallville is an unknown quantity at this point

Solved Threads: 0

smallville smallville is offline

Offline

Newbie Poster

Help w/ for loop.

Oct 6th, 2005

I'm trying to put together this program that creates a for loop but my end result is not positioned the way I need it like this but flipped around so it looks like a christmas tree effect.

*
**
***
****
*****

Please help I'm still learning and I can't figure it out for the life of me!

Source code:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
 
using namespace std;
 
int main()
{
	int i, j, lines;
 
    cout << "This Program creates Christmas Trees." << endl;
 
	do
	{
		cout << "Please enter a number between 1 and 30" << endl;
		cin  >> lines; 
	}while (lines < 1 || lines > 30);
 
	for(j=1; j<=lines; j++)
	{
 
	   for(i=1; i<=40; i=i++)
	   {
	      cout << " ";
	   }
 
	   for(i=1; i<=j; i=i++)
	   {
		  cout << "*";
	   }
	   cout << endl;
	}
}
#include <iostream>

using namespace std;

int main()
{
	int i, j, lines;

    cout << "This Program creates Christmas Trees." << endl;

	do
	{
		cout << "Please enter a number between 1 and 30" << endl;
		cin  >> lines; 
	}while (lines < 1 || lines > 30);

	for(j=1; j<=lines; j++)
	{

	   for(i=1; i<=40; i=i++)
	   {
	      cout << " ";
	   }
	   
	   for(i=1; i<=j; i=i++)
	   {
		  cout << "*";
	   }
	   cout << endl;
	}
}

<< moderator edit: added code tags: [code][/code] >>

•

Join Date: Aug 2005

Posts: 598

Reputation: SpS is on a distinguished road

Solved Threads: 32

SpS

Offline

Posting Pro

Re: Help w/ for loop.

Oct 6th, 2005

In your for loops

change

Help with Code Tags

C++ Syntax (Toggle Plain Text)

i=i++  
to 
i++

code will work fine

•

Join Date: Aug 2005

Posts: 80

Reputation: Daishi is an unknown quantity at this point

Solved Threads: 2

Daishi

Offline

Junior Poster in Training

Re: Help w/ for loop.

Oct 6th, 2005

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
 
using namespace std;
 
int main()
{
  int i, j, lines;
 
  cout << "This Program creates Christmas Trees." << endl;
 
  do
    {
      cout << "Please enter a number between 1 and 30" << endl;
      cin  >> lines;
    }while (lines < 1 || lines > 30);
 
  for(j=0; j<lines; j++)
    {
      for(i=0; i<=j; i++)
        {
          cout << "*";
        }
      cout << endl;
    }
}
#include <iostream>

using namespace std;

int main()
{
  int i, j, lines;

  cout << "This Program creates Christmas Trees." << endl;

  do
    {
      cout << "Please enter a number between 1 and 30" << endl;
      cin  >> lines;
    }while (lines < 1 || lines > 30);

  for(j=0; j<lines; j++)
    {
      for(i=0; i<=j; i++)
        {
          cout << "*";
        }
      cout << endl;
    }
}

You were really close.

Just take out the first for loop, and the i=i++ is something you *do not* want to do (think about it).

-Fredric

•

Join Date: Oct 2005

Posts: 11

Reputation: smallville is an unknown quantity at this point

Solved Threads: 0

smallville smallville is offline

Offline

Newbie Poster

Re: Help w/ for loop.

Oct 6th, 2005

thanks, it works but it's showing like in the post... however I need it to look more like an equal triangle from the top down

**********

the reason the other one was there is to bring it to the center of the program. The extra spaces it what brought it to the middle.. I'm completely stuck.

•

Join Date: Aug 2005

Posts: 80

Reputation: Daishi is an unknown quantity at this point

Solved Threads: 2

Daishi

Offline

Junior Poster in Training

Re: Help w/ for loop.

Oct 7th, 2005

Err', sorry, reread your post more carefully..if you want a christmas tree effect, then you need to include that for loop I said to leave out, but set the initial value of i to j in it, change 40 to lines, and increment i correctly. Then you have to make one little change to the second for loop and you should get a Christmas tree. Ok, no more hints!

-Fredric

•

Join Date: Oct 2005

Posts: 11

Reputation: smallville is an unknown quantity at this point

Solved Threads: 0

smallville smallville is offline

Offline

Newbie Poster

Re: Help w/ for loop.

Oct 7th, 2005

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
 
using namespace std;
 
int main()
{
	int i, j, lines;
 
    cout << "This Program creates Christmas Trees." << endl;
 
	do
	{
		cout << "Please enter a number between 1 and 30" << endl;
		cin  >> lines; 
	}while (lines < 1 || lines > 30);
 
	for(j=1; j<=lines; j++)
	{
 
	   for(i=1; i<=lines; i++)
	   {
	      cout << " ";
	   }
 
	   for(i=1; i<=j; i++)
	   {
		  cout << "*";
	   }
	   cout << endl;
	}
}
#include <iostream>

using namespace std;

int main()
{
	int i, j, lines;

    cout << "This Program creates Christmas Trees." << endl;

	do
	{
		cout << "Please enter a number between 1 and 30" << endl;
		cin  >> lines; 
	}while (lines < 1 || lines > 30);

	for(j=1; j<=lines; j++)
	{

	   for(i=1; i<=lines; i++)
	   {
	      cout << " ";
	   }
	   
	   for(i=1; i<=j; i++)
	   {
		  cout << "*";
	   }
	   cout << endl;
	}
}

I tried but I'm still getting the same effect. What am I doing wrong? Is the second loop the problem now?

•

Join Date: Aug 2005

Posts: 80

Reputation: Daishi is an unknown quantity at this point

Solved Threads: 2

Daishi

Offline

Junior Poster in Training

Re: Help w/ for loop.

Oct 7th, 2005

I assume you have the left side of the christmas tree. What you need is the right side? You just need to print out twice as many stars in that case.

0: *
1: ***
2

****

-Fredric

•

Join Date: Jun 2005

Posts: 16

Reputation: drock9975 is an unknown quantity at this point

Solved Threads: 1

drock9975

Offline

Newbie Poster

Re: Help w/ for loop.

Oct 9th, 2005

[QUOTE=smallville]

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
 
 
	for(j=1; j<=lines; j++)
	{
 
	   for(i=1; i<=lines; i++)
	   {
	      cout << " ";
	   }
 
	   for(i=1; i<=j; i++)
	   {
		  cout << "*";
	   }
	   cout << endl;
	}
}

	for(j=1; j<=lines; j++)
	{

	   for(i=1; i<=lines; i++)
	   {
	      cout << " ";
	   }
	   
	   for(i=1; i<=j; i++)
	   {
		  cout << "*";
	   }
	   cout << endl;
	}
}

the problem is with the for loops and the numbers you are using for the test program

if the first for loop
for(i=1; i<=lines; i++)
{
cout << " ";
}

the number for lines never changes so you are always moving over the same amount of spaces before printing out your stars... try making a temp variable that starts off equal to lines but decrements after both for loops are executed

the second for loop you want to print out stars that are double the amount you currently are; however, if you just simply attempt to print out double stars you will get a top of the tree that looks like this **
so you don't want just 2*j

•

Join Date: Oct 2005

Posts: 11

Reputation: smallville is an unknown quantity at this point

Solved Threads: 0

smallville smallville is offline

Offline

Newbie Poster

Re: Help w/ for loop.

Oct 11th, 2005

man I've been racking my brains trying to fix this program without having to post so I would learn it but I have tried so many different ways in doing it and it still doesn't work for me

:cry:

* ** *** **** *****

I need it to not double but to add one to each line for however many lines you are asking the program to create.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
 
using namespace std;
 
int main()
{
	int i, j, lines;
 
    cout << "This Program creates Christmas Trees." << endl;
 
	do
	{
		cout << "Please enter a number between 1 and 30" << endl;
		cin  >> lines; 
	}while (lines < 1 || lines > 30);
 
	for(j=1; j<=lines; j++)
	{
 
	   for(i=1; i<=lines; i++)
	   {
	      cout << " ";
	   }
 
	   for(i=1; i<=j; i++)
	   {
		  cout << "*";
	   }
	   cout << endl;
	}
}
#include <iostream>

using namespace std;

int main()
{
	int i, j, lines;

    cout << "This Program creates Christmas Trees." << endl;

	do
	{
		cout << "Please enter a number between 1 and 30" << endl;
		cin  >> lines; 
	}while (lines < 1 || lines > 30);

	for(j=1; j<=lines; j++)
	{

	   for(i=1; i<=lines; i++)
	   {
	      cout << " ";
	   }
	   
	   for(i=1; i<=j; i++)
	   {
		  cout << "*";
	   }
	   cout << endl;
	}
}