Thread: help with bubble sort 2D array

Code:

/*
   Dang Vo
   Lab 2
   [email protected]
*/

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

#define MAX 50
#define LEN 20
#define NUM_JUDGE 5
#define INCLUDE_JUDGE 3

int getData(FILE* spData, char name[][LEN], float difficulty[], float score[][NUM_JUDGE]);
void BubbleSort(float score[][NUM_JUDGE], int numDiver);
void Caltotal(float total[],float difficulty[], float score[][NUM_JUDGE]);
void printData(float total[], char name[][LEN], float score[][NUM_JUDGE], int size);
void printHeader();

int main(void)
{
    // Global Declarations
    FILE*spData;
    char name[MAX][LEN];
    float difficulty[MAX];
    float score[MAX][NUM_JUDGE];
    float total[MAX];
    int numDiver = 0;
	int size =4;
    //statement
    if((spData=fopen("DIV1.txt","r"))== NULL)
     {
          printf("\n Error opennning file!\n");
          exit(100);
     }
    else
    {
        printf("opened file!\n");
    }
    // function calls
    numDiver = getData(spData, name, difficulty, score);
    Caltotal(total,difficulty, score);
    printHeader();
    printData(total, name, score, numDiver);

    fclose(spData);
    int i;
    scanf("%d", &i);


return 0;
}


/*===============================getdata=====================================
Pre: SpData is oppened,
Post:
*/

int getData(FILE* spData, char name[][LEN], float difficulty[], float score[][NUM_JUDGE])

{
     int i=0;
     int j=0;


     while (i < MAX && (fscanf(spData,"%c", &name[i][0]) != EOF))
     {

            for(j = 1; j < LEN; j++)
            {
                fscanf(spData,"%c", &name[i][j]);
            }

            fscanf(spData,"%f", &difficulty[i]);
              for(j = 0; j < NUM_JUDGE; j++)
              {
                  fscanf(spData,"%f\n", &score[i][j]);

              }


            i++;
        }

    return i;
    BubbleSort(score, i);
}


/*===============================BubbleSort==================================
Pre:
Post:
*/
void BubbleSort(float score[][NUM_JUDGE], int size)
{
    int current;
    float temp;
    int walk;

        for(current = 0; current < size; current++)
			
        {
            for(walk = size; walk >= current; walk--)
                if(score[current][walk] < score[current][walk-1])
                {
                    temp                   = score[current][walk];
                    score[current][walk]   = score[current][walk-1];
                    score[current][walk-1] = temp;
                }
        }
		


    return;
}


/*===============================Caltotal======================================
Pre:
Post:
*/
void Caltotal(float total[],float difficulty[], float score[][NUM_JUDGE])
{
    // Local Declarations
    int i;
    int j;
    float temp = 0;
    for(i = 0; i < MAX; i++)
    for(j =0; j < INCLUDE_JUDGE; j++)
       {
           temp += score[i][j+1];
       }

      total[i] = temp * difficulty[i] / 3;
return;
}


/*===============================printHeader======================================
Pre:
Post:
*/
void printHeader()
{
// Local Declaration
    FILE*fpOut;

// Local Statments
    if(!(fpOut = fopen("output.txt", "w")))
        printf("Error writing output.txt"); //checks to see if output.txt opens

    fprintf(fpOut, "Dang Khoa Vo [email protected]          Lab#2\n\n");

    fprintf(fpOut, "NAME                  Scores         Total Score\n");
    fprintf(fpOut, "====================  ===  ===  ===  ===========\n");

    fclose(fpOut);

    return;
}

/*===============================PrintData=====================================
Pre:
Post:
*/

void printData(float total[], char name[][LEN], float score[][NUM_JUDGE], int numDiver)
{
// Local Declaration
    FILE*fpOut;
    int i,n;

// Local Statments
    if(!(fpOut = fopen("output.txt", "a")))
        printf("Error writing output.txt"); //checks to see if output.txt opens

    for (i=0; i< numDiver;i++)
        {
         for(n = 0; n < LEN; n++)
                fprintf(fpOut, "%c", name[i][n]);
         for(n = 0; n < 3; n++)
                fprintf(fpOut, "  %3.1f", score[i][n]);

         fprintf(fpOut, "     %5.2f", total[i]);
         fprintf(fpOut, "\n");
        }

    fprintf(fpOut, "\n");
    fclose(fpOut);

    return;
}

so i wanted to sort the last 5 number of each row of the input data from the attach file
but my sort function does not work can anyone tell me how to fix this problem could you give me an example of sorting 2d array using bubble sort. thank you

Function getData() returns before calling BubbleSort(), so BubbleSort() is never called.

But if BubbleSort() were called, it would access element score[.][size], which is beyond that end of data.
If there are N elements in an array, you index them 0 to N-1.

like this ?

Code:

/*
   Dang Vo
   Lab 2
   [email protected]
*/

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

#define MAX 50
#define LEN 20
#define NUM_JUDGE 5
#define INCLUDE_JUDGE 3

int getData(FILE* spData, char name[][LEN], float difficulty[], float score[][NUM_JUDGE]);
void BubbleSort(float score[][NUM_JUDGE], int numDiver);
void Caltotal(float total[],float difficulty[], float score[][NUM_JUDGE]);
void printData(float total[], char name[][LEN], float score[][NUM_JUDGE], int numDiver);
void printHeader();

int main(void)
{
    // Global Declarations
    FILE*spData;
    char name[MAX][LEN];
    float difficulty[MAX];
    float score[MAX][NUM_JUDGE];
    float total[MAX];
    int numDiver = 0;
	int size =4;
    //statement
    if((spData=fopen("DIV1.txt","r"))== NULL)
     {
          printf("\n Error opennning file!\n");
          exit(100);
     }
    else
    {
        printf("opened file!\n");
    }
    // function calls
    numDiver = getData(spData, name, difficulty, score);
    Caltotal(total,difficulty, score);
    printHeader();
    printData(total, name, score, numDiver);

    fclose(spData);
    int i;
    scanf("%d", &i);


return 0;
}


/*===============================getdata=====================================
Pre: SpData is oppened,
Post:
*/

int getData(FILE* spData, char name[][LEN], float difficulty[], float score[][NUM_JUDGE])

{
     int i=0;
     int j=0;


     while (i < MAX && (fscanf(spData,"%c", &name[i][0]) != EOF))
     {

            for(j = 1; j < LEN; j++)
            {
                fscanf(spData,"%c", &name[i][j]);
            }

            fscanf(spData,"%f", &difficulty[i]);
              for(j = 0; j < NUM_JUDGE; j++)
              {
                  fscanf(spData,"%f\n", &score[i][j]);

              }


            i++;
        }
	BubbleSort(score, i);
    return i;
    
}


/*===============================BubbleSort==================================
Pre:
Post:
*/
void BubbleSort(float score[][NUM_JUDGE], int numDiver)
{
    int i;
    float temp;
    int walk;

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

        {
            for(walk = NUM_JUDGE-1; walk >= 0; walk--)
                if(score[i][walk] < score[i][walk-1])
                {
                    temp             = score[i][walk];
                    score[i][walk]   = score[i][walk-1];
                    score[i][walk-1] = temp;
                }
        }
		


    return;
}


/*===============================Caltotal======================================
Pre:
Post:
*/
void Caltotal(float total[],float difficulty[], float score[][NUM_JUDGE])
{
    // Local Declarations
    int i;
    int j;
    float temp = 0;
    for(i = 0; i < MAX; i++)
    for(j =0; j < INCLUDE_JUDGE; j++)
       {
           temp += score[i][j+1];
       }

      total[i] = temp * difficulty[i] / 3;
return;
}


/*===============================printHeader======================================
Pre:
Post:
*/
void printHeader()
{
// Local Declaration
    FILE*fpOut;

// Local Statments
    if(!(fpOut = fopen("output.txt", "w")))
        printf("Error writing output.txt"); //checks to see if output.txt opens

    fprintf(fpOut, "Dang Khoa Vo [email protected]          Lab#2\n\n");

    fprintf(fpOut, "NAME                  Scores         Total Score\n");
    fprintf(fpOut, "====================  ===  ===  ===  ===========\n");

    fclose(fpOut);

    return;
}

/*===============================PrintData=====================================
Pre:
Post:
*/

void printData(float total[], char name[][LEN], float score[][NUM_JUDGE], int numDiver)
{
// Local Declaration
    FILE*fpOut;
    int i,n;

// Local Statments
    if(!(fpOut = fopen("output.txt", "a")))
        printf("Error writing output.txt"); //checks to see if output.txt opens

    for (i=0; i< numDiver;i++)
        {
         for(n = 0; n < LEN; n++)
                fprintf(fpOut, "%c", name[i][n]);
         for(n = 0; n < 3; n++)
                fprintf(fpOut, "  %3.1f", score[i][n]);

         fprintf(fpOut, "     %5.2f", total[i]);
         fprintf(fpOut, "\n");
        }

    fprintf(fpOut, "\n");
    fclose(fpOut);

    return;
}

but the sort function still doesnt work though is there anything wrong with the logic in sort fucntion ?

A bubble sort usually involves two 'for' loops to sort the same array. You've got each loop doing unrelated things. Also, 'walk" goes down to zero yet you are accessing [walk - 1] which is out-of-range of the array.

while your at it can you tell me what i did wrong for my calctotal function also and i fixed the sort function it worked now cant really see any mistake myself now since my eyeball is rolling out. i havent sleep the whole night

This bubble sort function is operating on a two-dimensional array.
It's not clear what the correct result is.

It loops through the divers (first index) once, so I guess we want to sort the divers for each judge (second index) independent of the other judges. OK.

But that means it's really doing a sort per diver. But it only does one loop within the diver loop. So it's only doing one pass of the bubble sort per diver.

There should be a loop between the two. The inner loop should be repeated until there are no swaps.

And nonoob is right, the inner loop is accessing data outside the array bounds.