Help writing a program

This is a discussion on Help writing a program within the C Programming forums, part of the General Programming Boards category; I need help writing a program. The program calls for a user to be asked a width and height to ...

  1. #1
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    Help writing a program

    I need help writing a program. The program calls for a user to be asked a width and height to make a table of asterisks. The height can ONLY be 3 or 5, and the width can be between 4-40. The table must be out of asterisks. Here is the program I have so far, except i need to replace the word "width" with the desired width of asterisks...How can I do this?

    Code:
    "pe3.c" 23 lines, 228 characters
         6  #include <stdio.h>
         7
         8  int main(void)
         9
        10  {
        11
        12  int height, width;
        13
        14  printf("Enter width:");
        15  scanf("&#37;d", &width);
        16  printf("Enter height:");
        17  scanf("%d", &height);
        18
        19  if (height == 3)
        20  printf("%d\n", width);
        21  printf("*%d*\n", width);
        22  printf("*%d*\n", width);
        23
        24  return 0;
        25
        26  }


    This is what the program is supposed to make:

    Code:
    Enter width: 20
    Enter height: 3
    ********************
    *                  *
    *                  *

  2. #2
    Jack of many languages Dino's Avatar
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    You'll need a loop. Do you know how to code a "for" loop?
    Mac and Windows cross platform programmer. Ruby lover.

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    12/20: Mario F.:I never was, am not, and never will be, one to shut up in the face of something I think is fundamentally wrong.

    Amen brother!

  3. #3
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    The instructor said I would need a loop. Can you give me an example of what I need to do?At the rate I am going I will be here all night. What I am doing is wrong I think.

    Code:
         6  #include <stdio.h>
         7
         8  int main(void)
         9
        10  {
        11
        12  int height, width;
        13
        14  printf("Enter width:");
        15  scanf("&#37;d", &width);
        16  printf("Enter height:");
        17  scanf("%d", &height);
        18
        19  if (width == 4)
        20  printf("****/n");
        21  else if (width == 5)
        22  printf("*****/n");
        23  else if (width == 6)
        24  printf("******/n");
        25  else if (width == 7)
        26  printf("*******/n");
        27  else if (width == 8)
        28  printf("********/n");
        29  else if (width == 9)
        30  printf("*********/n");
        31  else if (width == 10)
        32  printf("**********/n");
        33  else if (width == 11)
        34  printf("***********/n");

  4. #4
    i dont know Vicious's Avatar
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    Loops would work something like this.

    Code:
    ...
    int i = 0;
    int j = 0;
    for(i = 0; i < height; i++) {
        for(j = 0; j < width; j++) {
            printf("*");
        }
        printf("\n");
    }
    ...
    Something along those lines should work.
    What is C++?

  5. #5
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    I understand the for loop. My problem is trying to work with * rather than a number...Can I set an int such as width = * /

  6. #6
    i dont know Vicious's Avatar
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    Well the number will tell your loop how many times to loop. Then inside the loop you can print your "*". This will print the "*" every iteration.

    So when you get the users input, and you get the width, you lloop width amount of times and print "*".
    What is C++?

  7. #7
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    Ok but wouldn't this leave more of a "filled box shape"? I need the inside to be empty so it looks like a table

    The code you sent me should output this I believe


    Code:
    Enter width:10
    Enter height:3
    **********
    **********
    **********
    Needed

    Code:
    Enter width: 10
    Enter height: 3
    **********
    *        *
    *        *

  8. #8
    CSharpener vart's Avatar
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    putc(' '); will print a space character
    putc('*') - star cgharacter - you should mix them for the 2nd and futher lines
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  9. #9
    Jack of many languages Dino's Avatar
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    Here's a basic "for" loop. I'll write it, then I'll explain it.

    Code:
    int i ; 
    
    for ( i = 0 ; i < width ; i++ ) 
    {
        do-one-thing... ; 
    }
    
    some-next-instruction ;
    The code in RED is required for every "for" loop. (There is a shortcut to leave off the curly braces, but I won't get into that).

    The "for" says to loop some number of times. The parens enclose the INITIALIZER, the CONDITION and the INCREMENT, in that order.

    To start the loop, you set up an initializer. It is typical in a loop to control it with an INT. Here, variable i is the int. We set it with an initial values of 0. This is the most common thing to do.

    The flow of execution is this:
    1) the initializer is performed (this is only done once)
    2) the condition is checked
    3) if the condition is TRUE, then the code between the braces is executed. If the condition if false, then the loop is done, and control passes to the next instruction after the last curly brace.
    4) If the code between the braces was executed because the condition was true, then the increment is performed. The process repeats again, starting with step 2 above.

    So, let's take a simple example. Let's say you wanted to do the same thing (like print a '*') 5 times. You would initialize i to 0, you would set a condition for i to be less than 5 (because counting from 0 to 4 is "5 times"), and you would set an increment to bump i by one each loop.

    Does that make sense?

    This is just the very basics, but should be enough to get you going in the right direction.

    Todd

    EDIT - if not, hopefully the other posters who posted will have helped - who posted while I was writing this!! Man, you guys are fast!
    Mac and Windows cross platform programmer. Ruby lover.

    Quote of the Day
    12/20: Mario F.:I never was, am not, and never will be, one to shut up in the face of something I think is fundamentally wrong.

    Amen brother!

  10. #10
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    Can I put whatever I want where the green text is? I need the width to be between 4 and 40.

    So i == 4 < width < 40 ?

  11. #11
    Jack of many languages Dino's Avatar
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    You should validate the width prior to entering the loop.
    Mac and Windows cross platform programmer. Ruby lover.

    Quote of the Day
    12/20: Mario F.:I never was, am not, and never will be, one to shut up in the face of something I think is fundamentally wrong.

    Amen brother!

  12. #12
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    Ok thank you. Now I just have to work on where to put the printf(" "); at.

    Thanks

    Code:
         6  #include <stdio.h>
         7
         8  int main(void)
         9
        10  {
        11
        12  int height, width;
        13  int i = 0;
        14  int j = 0;
        15
        16  printf("Enter width:");
        17  scanf("&#37;d", &width);
        18  printf("Enter height:");
        19  scanf("%d", &height);
        20
        21  for (i = 0; i < height; i++) {
        22          for(j = 0; j < width; j++) {
        23                  printf("*");
        24          }
        25          printf("\n");
        26  }
        27
        28  printf("PROGRAM ENDS\n");
        29  return 0;
        30
        31  }
    Last edited by alex1067; 04-02-2008 at 11:55 PM.

  13. #13
    i dont know Vicious's Avatar
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    When you print the *, compare j and width to see where you are.

    If i is 0, don't worry about the check, after that, if j is equal to 0 or j is equal to width you can print *, else you can print ' '.
    What is C++?

  14. #14
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    Can anyone please show me where to put the printf(" ") in my code?

  15. #15
    C++まいる!Cをこわせ! Elysia's Avatar
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    Make a flowchart, translate your code into the flowchart, insert appropriate spaces into flowchart, translate into code.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

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