i am having trouble

[snowball]

hey i am new to the forum and i have being studying c for about a month now, and i need help with a part of a programe? here is the question:


An assessor is interested to compare the results of the same group of students at three
different modules. Write a program that reads the average grade for each of the three
modules and displays statistics in the order of their results in the following format.

NAME average
EM103 60
EM106 50
EM108 45

im not asking you to do the question, i want to know how to get the grades in order and have the subject stay along side them, here is what i have written so far

#include<stdio.h>
#include<string.h>
int main ()

{
    int i,j,t;
    float avg1, avg2, avg3;
    char mod1[] = {"em108"}, mod2[] = {"em109"}, mod3[]= {"em102"};


    printf("%s\t", mod1);
    scanf("%f", &avg1);
    printf("%s\t", mod2);
    scanf("%f", &avg2);
    printf("%s\t", mod3);
    scanf("%f", &avg3);

    printf("\nmodule\t grade\n");
    printf("%s    %.2f\n", mod1, avg1);
    printf("%s    %.2f\n", mod2, avg2);
    printf("%s    %.2f\n", mod3, avg3);



return 0;
}

i have been able to get the grades and module to be beside each other but as i said i don't know how to get them in order.

my teacher told me to use the strcpy function but i haven't been able to find any good examples on the internet or in any books, and any help at all would be a great help. thank you.

[whiteflags]

>> i want to know how to get the grades in order

Use a sort function.

>> and have the subject stay along side them

Use a struct.

[Adak]

Welcome to the forum, Snowball!

This is a classic "parallel arrays" problem. Strings in the names array, have to stay in order, with the numbers in the grades array. (structs are also good, but this is a parallel array problem).

Normally, when you sort, you move one item (the swap), if it's out of order. For this program, you need to move two items, if a grade is out of order:

1) The grade (obviously), and 2) the name that goes with that grade.

How are you doing with this?

[whiteflags]

(structs are also good, but this is a parallel array problem)

What, is there a difference?

From http://en.wikipedia.org/wiki/Parallel_array:

In computing, a parallel array is a data structure for representing arrays of records. It keeps a separate, homogeneous array for each field of the record, each having the same number of elements. Then, objects located at the same index in each array are implicitly the fields of a single record.

C has structs, which are records, and parallel arrays emulate records.

[Adak]

Yes, there's a difference. Parallel arrays are taught first, and structs are taught after that.



The reason parallel arrays are taught first, is because they want the student to learn that association between index number in one array, with the data at the index number of another array, and how to use that to their advantage.

While structs are generally much better in a program design, there are places where structs just suck eggs, and you need to use parallel arrays.

[quzah]

What, is there a difference?

1. Ease of use. If I want to pass a particular bit of info function, I only need one argument with a structure. Otherwise I need as many arguments as there are arrays.

2. Size. The parallel arrays are probably smaller in memory. There is no padding.

3. Convention (how you us them):

eacharrayname[ slot ]

vs

arrayname[ slot ].each



Quzah.

[snowball]

hey everybody, i got the result i needed using a structure and bubble sort. i still dont know were the strcpy function comes into this program. but thanks everybody for all your help

[quzah]

strcpy is used to copy strings from one place to another. You can't do this:

char array[ SOMESIZE ];

array = "somestring";

You cannot use the assignment operator to assign more than one element to an array at a time (other than when you first declare the variable), so you have to do it one element at a time.

strcpy does this for you, by taking two arrays and looping through the second one to copy it to the first one.


Quzah.