Thread: Clueless on an Assignment

  1. #1
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    Clueless on an Assignment

    My assignment is to do the following:

    Write a program that executes multiplication of two integers entered by the user , by
    using ONLY the addition operation.
    So, for example if the inputs are 3 and 4, the program will execute 3 times addition of
    4: 4+4+4.

    I have to do it using the "while" function. I understand the basic concept of the while function but I have no clue how to do this. Please help me understand it better.

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    Well, if you understand the basic function of a while loop why don't you throw some code together. Go ahead and make an educated guess and post some code. We will go from there.
    Quote Originally Posted by anduril462 View Post
    Now, please, for the love of all things good and holy, think about what you're doing! Don't just run around willy-nilly, coding like a drunk two-year-old....
    Quote Originally Posted by quzah View Post
    ..... Just don't be surprised when I say you aren't using standard C anymore, and as such,are off in your own little universe that I will completely disregard.
    Warning: Some or all of my posted code may be non-standard and as such should not be used and in no case looked at.

  3. #3
    [](){}(); manasij7479's Avatar
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    while isn't a function, it is a loop construct.

    Do it as you'd do it by hand...suppose....( m x n ):
    Count from 1 to n or 0 to n-1.
    Each time add m to the sum, which was initially 0.

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    Quote Originally Posted by AndrewHunter View Post
    Well, if you understand the basic function of a while loop why don't you throw some code together. Go ahead and make an educated guess and post some code. We will go from there.

    Code:
    #include <stdio.h>
    #include "genlib.h"
    #include "simpio.h"
    
    main()
    {
          int num1, num2, sum;
          
          printf ("Enter two numbers to multiply: ");
          num1 = GetInteger();
          num2 = GetInteger();
          sum = 0;
          while (sum < num1 * num2)
          {
                sum = + num1 + num1;
                }
          printf ("product = %d.\n", sum);
          getchar();
          }
    There you are, Andrew. I had this before I asked the question and it wasn't working. I've tried everything that I could think of. That is why I asked the question.

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    Quote Originally Posted by PYROMANIAC702 View Post
    .......
    There you are, Andrew. I had this before I asked the question and it wasn't working. I've tried everything that I could think of. That is why I asked the question.
    Hmm.....good way to get help.
    Quote Originally Posted by anduril462 View Post
    Now, please, for the love of all things good and holy, think about what you're doing! Don't just run around willy-nilly, coding like a drunk two-year-old....
    Quote Originally Posted by quzah View Post
    ..... Just don't be surprised when I say you aren't using standard C anymore, and as such,are off in your own little universe that I will completely disregard.
    Warning: Some or all of my posted code may be non-standard and as such should not be used and in no case looked at.

  6. #6
    and the hat of int overfl Salem's Avatar
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    Try it with a for 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.

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    Quote Originally Posted by AndrewHunter View Post
    Hmm.....good way to get help.
    NO! I wasn't being rude in any way. I'm sorry if i offended you, but I was just pointing out that I tried it before I asked. Please help me.

  8. #8
    Lurking whiteflags's Avatar
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    Code:
     sum = ???? + num1 + num1;
    Should be adding three things.

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    You could try this while loop:

    Code:
    while(counter<=num1)
       {
            sum += num2;
       }
    I don't know if this works,,

  10. #10
    ATH0 quzah's Avatar
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    Quote Originally Posted by jannr View Post
    I don't know if this works,,
    I know it doesn't work, since you never change counter or num1 inside your loop.


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

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    Quote Originally Posted by quzah View Post
    I know it doesn't work, since you never change counter or num1 inside your loop.


    Quzah.
    lol,, I forgot,, haha sorry,,

    Code:
    while(counter<=num1)
    {
        sum += num2;
        counter++;
    }
    I guess this is right,, ^^

  12. #12
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    Quote Originally Posted by PYROMANIAC702 View Post
    Code:
    #include <stdio.h>
    #include "genlib.h"
    #include "simpio.h"
    
    main()
    {
          int num1, num2, sum;
          
          printf ("Enter two numbers to multiply: ");
          num1 = GetInteger();
          num2 = GetInteger();
          sum = 0;
          while (sum < num1 * num2)
          {
                sum = + num1 + num1;
                }
          printf ("product = %d.\n", sum);
          getchar();
          }
    There you are, Andrew. I had this before I asked the question and it wasn't working. I've tried everything that I could think of. That is why I asked the question.
    Ok, think about this....

    You have a start value... you have a counter... how can you use them to construct a simple loop?

    Code:
    int x = 234;  // multiply
    int y = 37;  // by
    int z = 0;   // answer
    
    while (y--)
       z += x;

  13. #13
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    Quote Originally Posted by jannr View Post
    lol,, I forgot,, haha sorry,,

    Code:
    while(counter<=num1)
    {
        sum += num2;
        counter++;
    }
    I guess this is right,, ^^
    actually it should be like that
    Code:
    sum = 0;
    counter = 1;
    while(counter<=num1)
    {
        sum += num2;
        counter++;
    }
    Last edited by agathery; 07-14-2011 at 07:31 AM.

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