Thread: Average of Values in an Array: Using SIZE_MAX?

  1. #1
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    Average of Values in an Array: Using SIZE_MAX?

    Hello! I am attempting to write some code that will find the average of values in an array. Using my textbook, I found some code that took an array and found the mean, median, and mode. I attempted to modify that example to be used simply for finding the mean for an array with 5 values. I wanted to be able to call it from main with a prototype rather than have it in main(). I also want the fucntion to work with any size array. I thought that I could solve this by using SIZE_MAX, which I have never used before and only found through a google search. I have been recieving Before I had included SIZE_MAX, the code did run with SIZE originally defined as 99. However, when solving for the average, the numbers were very off.

    Here are some of the errors I recieved when trying to run the code:

    note: this is the location of the previous definition
    # define SIZE_MAX (18446744073709551615UL)

    error: expected expression before ‘;’ token
    for (size_t j = 0; j < SIZE_MAX; ++j)

    error: expected expression before ‘)’ token
    printf("The average of the array is %4f.\n", (double) total / SIZE_MAX);



    I would appreciate any insight on the use of SIZE_MAX in C or information on an error in my math that may have messed things up. Thank you in advance for all help provided. It is greatly appreciated.

    Code:
    #include <stdio.h>#include <stdint.h>
    #include <limits.h>
    #define SIZE_MAX //Do I need this????????
    
    
    void mean(const unsigned int array[]);
    
    
    int main(void)
    {
        unsigned int array[] = {707, 3000, 5, 1, 3};
        
        mean(array);
    }
    
    
    void mean(const unsigned int array[])
    {
        unsigned int total = 0;
        
        for (size_t j = 0; j < SIZE_MAX; ++j)
        {
            total += array[j];
        }
        
        printf("The average of the array is %4f.\n", (double) total / SIZE_MAX);
    }
    Last edited by G707; 05-05-2019 at 01:28 PM.

  2. #2
    C++ Witch laserlight's Avatar
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    This SIZE_MAX thing is a red herring. If you want to cater for arrays of different sizes, have a size parameter.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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