Thread: Need Help With Simple Iteration Program

  1. #1
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    Need Help With Simple Iteration Program

    I have been asked to write a program that creates the following pattern without simply printing this sequentially :

    1 2 3 4 5 6 7 8 9
    1 2 3 4 5 6 7 8
    1 2 3 4 5 6 7
    1 2 3 4 5 6
    1 2 3 4 5
    1 2 3 4
    1 2 3
    1 2
    1


    So far this is my code but it doesn't work. I am meant to use either a for loop or a while loop.

    Code:
    #include <stdio.h>
    
    int main()
    {
    	int i;
    	int max;
    
    	scanf("%d%c", &max);
    
    	while(max <= 10)
    	{
    		for(i = 1; i < max; i++)
    		{
    			printf("%d\n", i);
    			max--;
    			printf("%d\n", i);
    		}
    	}
    	
    	return(0);
    }
    Can anyone help me?

  2. #2
    and the hat of int overfl Salem's Avatar
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    Why are you comparing max to 10, when max is decreasing?

    You probably don't want to decrease max INSIDE your inner loop.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  3. #3
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    Code:
    #include <stdio.h>
    
    int main()
    {
    	int i;
    	int max;
    
    	scanf("%d%*c", &max);
    
    		for(i = 1; i < max; i++)
    		{
    			printf("%d", i);
    		}
    
    		return(0);
    }
    I have refined it to this which gives me the first line of the question.

    Can anybody tell me how to repeat it so that i obtain the pattern in the question?
    Last edited by rbreakey; 03-09-2011 at 05:25 AM.

  4. #4
    and the hat of int overfl Salem's Avatar
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    You modify the loop you had, not remove it altogether!
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  5. #5
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    Code:
    #include <stdio.h>
    
    int main()
    {
    	int i;
    	int max;
    
    	scanf("%d%*c", &max);
    
    	while(max <= 10 && max >=2)
    	{
    		for(i = 1; i < max; i++)
    		{
    			printf("%d", i);
    		}
    		
    		printf("%d\n");
    		max--;
    	}		
    	
    	return(0);
    }
    This gives me the right answer except it produces a 0 at the end of each line.

    Code:
    #include <stdio.h>
    
    int main()
    {
    	int i;
    	int max = 10;
    
    	while(max <= 10 && max >=2)
    	{
    		for(i = 1; i < max; i++)
    		{
    			printf("%d", i);
    		}
    		printf("\n");
    		max--;
    	}		
    	return(0);
    }
    This is my final code which produces the right result. Can anyone tell me if it looks ok? and if there is anything i need to modify. Cheers.
    Last edited by rbreakey; 03-09-2011 at 07:14 AM.

  6. #6
    and the hat of int overfl Salem's Avatar
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    It seems OK to me.

    One small nit is that the () around return 0 are redundant.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  7. #7
    Programming King Mr.777's Avatar
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    Whole code is working fine.....
    And Salem, does this () really matters in output???
    I don't think so...... And program shouldn't give 0 in the end....
    I made a dry run of this program and it's working nice....

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