Mean (average), median, and mode

jusmeehh · #1 15-Jun-2009, 21:19

Write a program to compute the aritmetic mean (average), median, and mode for up to 50 test scores. The data are contained in a text file. The program will also print a histogram of the scores.
The program should start with a function to read the data file and fill the array. Note that there may be fewer than 50 scores. This will require that the read function return the index for the last element in the array.
To determine the average. To determine the median, you mst first sort the array. The median is the score at last / 2 if last is an even inde and by averaging the scores at the floor and ceiling of last / 2 if last is odd. The mode is the score that occurs the most often. It can be determined as a byprodcut of building which score occurred most often. (Note that two scores can occur the same number of times.)

This is what I came up using Bloodshed Dev-C++:

CPP / C++ / C Code:

#include <stdio.h>
#include <stdlib.h>

double average (int ary[ ]);
void printAverage (int data[ ], int size, int lineSize);

int main (void)
{
	double avg;
	int    base[50] = {30, 70, 20, 40, 50, 10, 90, 80, 40, 100,
                      90, 30, 60, 80, 20, 90, 100, 50, 30, 20,
                      70, 10, 50, 70, 90, 20, 10, 90, 50, 80, 
                      40, 90, 20, 20, 30, 40, 60, 50, 70, 90,
                      100, 20, 30, 40, 50, 60, 70, 80, 90, 90};

	avg = average(base);
    printAverage (nums, size, 10);                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
	
	
    system ("pause");
    return 0;
}	

double average (int ary[ ])
{
	int sum = 0;
	for (int base = 0; base < 50; base++)
	     sum += ary[base];

	return (sum / 5.0);
}	

void printAverage (int data[], int size, int lineSize)
{
	int numPrinted = 0;

	printf("\n\n");
	for (int i = 0; i < size; i++)
	   {
	    numPrinted++;
	    printf("%2d ", data[i]);
	    if (numPrinted >= lineSize)
	       {
	        printf("\n");
	        numPrinted = 0;
	       } 
	   } 
	printf("\n\n");
	return;
}

davekw7x · #2 16-Jun-2009, 09:27

Quote:

Originally Posted by jusmeehh

...This is what I came up...

So what happened when you compiled it?

The title that you gave the thread is, "Need Help Asap With C Programming Project!!"

What kind of help would you like? The likelihood of getting help "Asap" might be improved if you ask specific questions rather than just posting the statement of the assignment along with some code that won't compile.

As far as the assignment itself, my approach would be to develop the code a step at a time.

Step number 1:

Quote:

The program should start with a function to read the data file and fill the array.

Regards,

Dave

admin · #3 17-Jun-2009, 04:13

Just a note to let you know that I edited the title of this thread.

Mexican Bob · #4 18-Jun-2009, 07:19

Quote:

Originally Posted by jusmeehh

Write a program to compute the aritmetic mean (average), median, and mode for up to 50 test scores. The data are contained in a text file. The program will also print a histogram of the scores.
The program should start with a function to read the data file and fill the array. Note that there may be fewer than 50 scores. This will require that the read function return the index for the last element in the array.
To determine the average. To determine the median, you mst first sort the array. The median is the score at last / 2 if last is an even inde and by averaging the scores at the floor and ceiling of last / 2 if last is odd. The mode is the score that occurs the most often. It can be determined as a byprodcut of building which score occurred most often. (Note that two scores can occur the same number of times.)

This is what I came up using Bloodshed Dev-C++:

You didn't read the part that said that there may be fewer than 50 scores. Your functions will need to know the length of the array.

As Dave mentioned, you need to read the values in from a file of scores.

Maybe this will help get you started:

CPP / C++ / C Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#ifndef __cplusplus
typedef char bool;
#endif

#ifndef TRUE
#define TRUE     (1)
#define FALSE    (0)
#endif

typedef int* INT_ARRAY;

void print_array(const INT_ARRAY pia, const size_t count)
{
    size_t i;
    if(pia != NULL && count > 0)
    {
        for(i = 0; i < count; i++)
        {
            printf("pia[%d] = %d\n", (int)i, pia[i]);
        }
    }
}

#define MAX(x, y) (x > y ? x : y)
#define MIN(x, y) (x < y ? x : y)

int compareGreaterOf(const void* pv1, const void* pv2)
{
    const int* p1 = (int*)pv1;
    const int* p2 = (int*)pv2;
    return (*p1 - *p2);
}

int mean(const int* p, const size_t len)
{
    size_t i;
    int avg = 0;
    if(len > 0 && p != NULL)
    {
	for(i = 0; i < len; i++)
	{
	    avg += p[i];
	}
	avg = avg/len;
    }
    return avg;
}

int median(int* p, const size_t len)
{
    int f, l, med = 0;
    
    if(len > 0 && p != NULL)
    {
	qsort(p, len, sizeof(int), compareGreaterOf);
	l = p[len-1];
	f = p[0];
	if(l % 2 == 0)
	{
	    med = l/2;
	}
	else
	{
	    med = (f + l)/2;
	}
    }
    return med;
}
    

int main()
{
    char* good                  = NULL;
    char value[16]		= {0};
    char filename[BUFSIZ]	= {0};
    int* p			= NULL;
    size_t l			= 0;
    int i			= 0;
    FILE* pfIn			= NULL;

    printf("Enter the filename from which to read scores: ");
    fgets(filename, sizeof(filename), stdin);
    filename[strlen(filename)-1] = '\0';

    pfIn = fopen(filename, "r");
    if(pfIn == NULL)
    {
	printf("Could not open file: %s\nExiting.", filename);
	exit(-1);
    }

    do
    {
        i = 0;
	good = fgets(value, sizeof(value), pfIn);
	if(!good)
	{
	    break;
	}
	value[strlen(value)-1] = '\0';
        i = atoi(value);
        if(errno != EINVAL && errno != ERANGE)
        {
            p = (int*)realloc(p, (sizeof(int) * (l + 1)));
            if(p != NULL)
            {
                p[l++] = i;
            }
        }
        if(feof(pfIn))
	{
	    break;
	}
    } while(TRUE);

    printf("Average score of %d scores is %d\n", (int)l, mean(p, l));
    printf("The median of %d scores is %d\n", (int)l, median(p, l));
    
    if(p != NULL)
    {
        free(p);
    }
    return 0;
}

Output:

Code:

bash-3.2$ ./mmm
Enter the filename from which to read scores: /tmp/scores.txt
Average score of 50 scores is 73
The median of 50 scores is 49

scores.txt:

Code:

Remember to "mix up" the scores so that you do not always have an even number at the end for your median tests (or a zero at the beginning, too)!

Note that I didn't do the mode and histogram parts.

MxB

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Mean (average), median, and mode

Re: Need Help Asap With C Programming Project!!

Re: Mean (average), median, and mode

Re: Mean (average), median, and mode