Star Program not working?

This is a discussion on Star Program not working? within the C Programming forums, part of the General Programming Boards category; I don't know what I did wrong....thought it looked good. Please help. Code: #include <stdio.h> int main () { int ...

  1. #1
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    Star Program not working?

    I don't know what I did wrong....thought it looked good. Please help.

    Code:
    #include <stdio.h> 
    
    int main ()
    {
    
    int star;
    int num;
    int a;
    int b;
    
    scanf("%d", &star);
    
    num = 0;
    while(num <= star){
     
    for (a=1; a<=star; a++)
    {
     printf("*");
    }
    printf("\n");
    star = star - 1;   
    num++;
    }
    return 0;
    }
    If I input 5 it outputs
    *****
    ****
    ***
    and then that is it.

    I need to know how come it won't output the last two
    **
    *

  2. #2
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    Your while loop has to go to a fixed number - star. Don't decrement star at all.
    In your for loop, you need to use another variable - not star. Maybe j or whatever.
    J is the variable you decrement after each for loop.

    It's also helpful if you work from 0 counters, rather than 1. Here, you start num with 0, but you start 'a' out at 1.

    You don't want to do that.

    Another tip, (use with the above), is to use just < or > as much as feasable. Not <= or >=. That decreases obo* errors, in general.

    *obo = off by one.
    Last edited by Adak; 01-19-2010 at 07:57 PM.

  3. #3
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    i am somewhat seeing what your saying. Could you give me an example....?

  4. #4
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    nevermind, I just figured it out. Thank you Adak. Could someone explain how to do it in the opposite direction?

    ex. 4
    *
    **
    ***
    ****

  5. #5
    ATH0 quzah's Avatar
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    Count the other way.


    Quzah.
    Hope is the first step on the road to disappointment.

  6. #6
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    Sure:

    Code:
      while (num < star) {
        for(i = 0; i < (star - num); i++) 
          putchar('*');
        putchar('\n');
        num++;
      }
    The quantity star - num removes the need for a separate variable.

  7. #7
    ATH0 quzah's Avatar
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    Time for some fun.
    Code:
    #include<stdio.h>
    int main( void )
    {
        int star = 0;
        
        printf( "Enter a number from 1-9: " );
        fflush( stdout );
        while( scanf( "%d", &star ) != 1 || star > 9 || star < 1 )
            fgetc( stdin );
    
        do
        {
            switch( star )
            {
                case 9: printf( "*" );
                case 8: printf( "*" );
                case 7: printf( "*" );
                case 6: printf( "*" );
                case 5: printf( "*" );
                case 4: printf( "*" );
                case 3: printf( "*" );
                case 2: printf( "*" );
                case 1: printf( "*" );
                default: printf( "\n" );
            }
        }
        while( star-- );
    
        return 0;
    }
    And because you know you want to, someone make a recursive one.


    Quzah.
    Hope is the first step on the road to disappointment.

  8. #8
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    that's funny, i was wondering how about doing the recursive one.

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