Thread: Sorting .an array

Dear all,

I found it quite difficult to handle a series of data without using arrays.

For example, if I want to store a group of 10 students and their marks, it will be easier for me to define two arrays, one for storing the student names and the other to store their marks.

For example, I can define the arrays as follows:

char studentName[10][31]; //store up to 10 names with

//maximum length for name up to 30 characters.

float studentMark[10];

I can assign values to those arrays as follows:

Code:

int i;

for(i=0; i<10; i++) 

{ 

	printf("Enter name for student #%d", i+1);

	scanf("%s", studentName[i]);

	printf("Enter mark for student #%d", i+1);

	scanf("%f", &studentMark[i]); 

 }

However, I got no idea how to sort the arrays such that it will print the name and the mark for the highest student at the top followed by the next highest and so on...

Anybody can help me on that?

Thanks in advance.

Cprogramming.com Tutorial: Structures Make an array of them.

You can simply modify the swap function in the sorting procedure.
But why not use something like a structure?

Thank you for your info Adak. I am the beginners in C programming and not familiar with structure and pointer.
Here are my coding which i do swap function on studentMark to get ascending order for studentMark.
Unfortunately, the studentName is not swap together. Are there any suggestion on how structure can help me to sorting studentName and studentMark together?

Code:

#include<stdio.h>
#include<conio.h>

main()
{
     char studentName[10][31];  //store up to 10 names with 
   	//maximum length for name up to 30 characters. 
     float studentMark[10]; 
     int i,j,hold;

    for(i=0; i<10; i++) 
    { 
    	printf("Enter name for student #%d", i+1);
     	scanf("%s", studentName[i]);
      	printf("Enter mark for student #%d", i+1);
       	scanf("%f", &studentMark[i]); 
        }
    for (i=0;i<=10-1;i++)    
    for (j=0; j<=10-2; j++)
    {
        if (studentMark[j]>studentMark[j+1])
        { 
            hold=studentMark[j];
            studentMark[j] = studentMark[j+1];
            studentMark[j+1] = hold;
            }
     }
     
     printf("\n List of student in ascending order\n");
     for (i=0; i<10; i++)
     {
          printf("%s\t\t%.0f\n", studentName[i], studentMark[i]);
          }
     getch(); 
     return 0;
}

In your inner sorting loop, you have a hold variable to temporarily hold the value of the mark that will be changed, in the array.

After you swap marks, you need to immediately swap names. Since names is a string variable, include <string.h> into your include file area, and you can use strcpy(), to copy the names, and keep the same parallel array format.

I don't use parallel arrays much, *however*, it's important to know how they can be used in a program. For that reason, I'd stick with parallel arrays, for this exercise. Code to include would look like:

Code:

char tempstr[31] = {'\0'};

for(i = .......) {
  for(j = ......) {
    if(marks[j] < marks[j+1] {
      //swap the marks, they're out of order
      hold = marks[j];
      marks[j] = marks[j+1];
      marks[j+1] = hold;

      //now swap the names  
      strcpy(tempstr, names[j]];
      strcpy(names[j], names[j+1]);
      strcpy(names[j+1], tempstr);
    }
  }
}

While it's pretty complete, the above code is not a working program, and is meant to show the general idea, not something to copy and paste and whoopee, it works.

IMO, it's better to work with parallel arrays, until you have been introduced to structs, and how to work with them, for two reasons:

1) It's a useful trick for problem solving, in it's own right. If you don't learn it now, you probably won't learn it later.

2) Sorting with an array of something you haven't studied yet, is just doing the right thing, in the wrong order. Learning should work by building on the known, not working with the unknown, to learn something new.

You'll just have to swap studentName whenever you swap studentMark.

Thanks for your guiding...i'll try as your suggestion..

Thanks adak, my coding are work which i can sort name and mark together based on your guide. It's interest me to learn fast on the chapter that i'm not studied yet to growth my knowledge, especially struct and pointer....

Thanks again.

You're quite welcome.

You have a good attitude, but try to work with the C subjects that your lessons are focusing on, right now. Structs and pointers will still arrive soon, and it's best if you REALLY know the elementary basics of C, before you start working with them.