Sorting Two Dimensional Arrays

I've made two C programs.
The first program writes a binary table to 'sales.dat'.
The second program is what I have a problem with.
I want to sort those numbers in two ways by reading the binary file created by the first program:
1. I want to display the top three number in each of the 12 rows.
(I was thinking of using selection sort for that, but I can't quite get it.)
2. I want to add every number in each column and display the top three sums and its product name.

Please help.

Here is the table I'm trying to base this program of:

Code:

---

          Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Note A 34  56 27 100 74 56 12 5 87 29 63 16
Note B 9 11 14 55 30 4 47 150 136 26 18 12
Note C 46 3 22 8 78 14 52 27 35 80 123 90
Ballpoin
t pen A 58 38 79 120 85 52 39 23 31 10 10 46
Ballpoin
t pen B 8 5 3 8 2 21 7 3 8 13 8 7
Ballpoin
t pen C 26 32 28 26 24 20 19 22 23 28 30 29
Pencil 12 19 54 51 41 36 20 28 3 5 7 32
Marker 22 14 53 21 25 23 22 180 31 6 213 58
Pencil
case 10 14 43 12 13 17 14 12 11 9 54 15
Erase A 21 20 28 17 19 14 13 12 17 18 14 11
Erase B 24 21 13 24 20 16 13 17 24 38 23 28

---

The program that writes the file:

Code:

---

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

int main(){

        FILE* fp;
        char filename[]="sales.dat";
        int a[11] [12] = {
                        {34, 56, 27, 100, 74, 56, 12, 5, 87, 29, 63, 16},
                        {9, 11, 14, 55, 30, 4, 47, 150, 136, 26, 18, 12},
                        {46, 3, 22, 8, 78, 14, 52, 27, 35, 80, 123, 90},
                        {58, 38, 79, 120, 85, 52, 39, 23, 31, 10, 10, 46},
                        {8, 5, 3, 8, 2, 21, 7, 3, 8, 13, 8, 7},
                        {26, 32, 28, 26, 24, 20, 19, 22, 23, 28, 30, 29},
                        {12, 19, 54, 51, 41, 36, 20, 28, 3, 5, 7, 32},
                        {22, 14, 53, 21, 25, 23, 22, 180, 31, 6, 213, 58},
                        {10, 14, 43, 12, 13, 17, 14, 12, 11, 9, 54, 15},
                        {21, 20, 28, 17, 19, 14, 13, 12, 17, 18, 14, 11},
                        {24, 21, 13, 24, 20, 16, 13, 17, 24, 38, 23, 28} };

        if(!(fp=fopen(filename, "wb"))){
                        printf("Can't open a file\n");
                        return -1;
                }

        if(fwrite(a, sizeof(int), 132, fp)!= 132){
                fclose(fp);
                printf("Can't write\n");
                return -1;
        }
        printf("Success to write!\n");
        fclose(fp);
}

---

The program I am having trouble with:

Code:

---

#include<stdio.h>

int main(){

        FILE *fp;
        char filename[]="sales.dat";
        int a[11] [12];
        int k[12];
        int sum[12];
        char str[11] [50] = {"Note A", "Note B", "Note C", "Ballpoint pen A", "Ballpoint pen B", "Ballpoint pen C",
                                "Pencil", "Marker", "Pencil case", "Erase A", "Erase B"};
        int i, j, tmp, min;

        if(!(fp=fopen(filename, "rb"))){
                printf("Can't open a file\n");
                return -1;
        }
        if(fread(a, sizeof(int), 132, fp)!=132){
                fclose(fp);
                printf("Can't read\n");
                return -1;
        }
        printf("Success to read!\n");
        fclose(fp);

        for(i=0;i<11;i++){
                for(j=0;j<12;j++){
                        printf("%5d", a[i] [j]);
                }
                printf("\n");
        }

        for(i=0;i<12;i++){
                min = i;
                for(j=i+1;j<11;j++){
                        if(a[0] [min]>a[0] [j]){
                                tmp = a[0] [min];
                                a[0] [min] = a[0] [i];
                                a[0] [i] = tmp;
                        }
                }
        }


        for(i=0;i<12;i++){
                for(j=0;j<11;j++){
                        sum[i]+=a[i] [j];
                        printf("%5d", a[i] [j]);
                }
                printf("\n");
        }
        return 0;
}

---

Welcome to the forum, Hufnagel! :cool:

What is the connection between the data? The first table seems to have each record with it's record fields across one row.

In the second program it's just data. What's the relationship between the two tables?

Could you show what output you're trying to get, from a 3 row example of the data and records? Your description doesn't make it clear to me.

Normally, if you want to show sorted output two or more different ways, you would either copy the original (to preserve the order it has), and then sort the duplicate table (or create a table of pointers, and sort "through" the pointers, or a separate index table).

Using a duplicate table is easiest, an index table is :cool: and perhaps easier, but using pointers is more fun.

We can help you with the sorting for sure, but I'm not clear what you want for your final output.

Quote:

---

Originally Posted by hufnagel

The first program writes a binary table to 'sales.dat'.
I want to sort those numbers in two ways by reading the binary file created by the first program:
1. I want to display the top three number in each of the 12 rows.
(I was thinking of using selection sort for that, but I can't quite get it.)
2. I want to add every number in each column and display the top three sums and its product name.

---

Two things to be aware of:
1. When a 2d-array is declared as MyArray[y][x], we say that MyArray has y rows and x columns.
2. C treats a 2d-array as if it is actually a 1d-array where each element is itself a row.

Sorting MyArray so that each row is in increasing order is straightforward. Let's call this operation arrsortrows(MyArray). To sort by column, here is a simple method:

1. Transpose MyArray into MyArray_T
2. Perform arrsortrows(MyArray_T)
3. Transpose MyArray_T into MyArray

Performing these operations in C is straightforward but tedious. Better to use functions. You should be able to adapt this example to solve your problem:

Code:

---

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

// arrprint(y, x, a[y][x]): print array a in tabular format
void arrprint(int y, int x, int a[y][x]);

// arrcopy(y, x, a, b): copy elements of a into b
void arrcopy(int y, int x, int a[y][x], int b[y][x]);

// arrtrans(y, x, a, aT): transpose a into aT
void arrtrans(int y, int x, int a[y][x], int aT[x][y]);

// arrsort(n, a[n]): sort a numerically elementwise
void arrsort(int n, int a[n]);

// arrsortrows(y, x, a[y][x]): sort a row-by-row
void arrsortrows(int y, int x, int a[y][x]);

// arrsortcolumns(y, x, a[y][x]): sort a column-by-column
void arrsortcolumns(int y, int x, int a[y][x]);

int main(int argc, char *argv[])
{
        int orig[11] [12] = {
                        {34, 56, 27, 100, 74, 56, 12, 5, 87, 29, 63, 16},
                        {9, 11, 14, 55, 30, 4, 47, 150, 136, 26, 18, 12},
                        {46, 3, 22, 8, 78, 14, 52, 27, 35, 80, 123, 90},
                        {58, 38, 79, 120, 85, 52, 39, 23, 31, 10, 10, 46},
                        {8, 5, 3, 8, 2, 21, 7, 3, 8, 13, 8, 7},
                        {26, 32, 28, 26, 24, 20, 19, 22, 23, 28, 30, 29},
                        {12, 19, 54, 51, 41, 36, 20, 28, 3, 5, 7, 32},
                        {22, 14, 53, 21, 25, 23, 22, 180, 31, 6, 213, 58},
                        {10, 14, 43, 12, 13, 17, 14, 12, 11, 9, 54, 15},
                        {21, 20, 28, 17, 19, 14, 13, 12, 17, 18, 14, 11},
                        {24, 21, 13, 24, 20, 16, 13, 17, 24, 38, 23, 28} };

    printf("Original array:\n");
    arrprint(11, 12, orig);
   
    printf("\nSorted by month (columnwise):\n");
    int bymonth[11][12];
    arrcopy(11, 12, orig, bymonth);
    arrsortcolumns(11, 12, bymonth);
    arrprint(11, 12, bymonth);
   
    printf("\nSorted by product (rowwise):\n");
    int byproduct[11][12];
    arrcopy(11, 12, orig, byproduct);
    arrsortrows(11, 12, byproduct);
    arrprint(11, 12, byproduct);
   
    return 0;
}

// numcmp: return negative number if a < b, nonnegative otherwise
static inline int numcmp(const void*a, const void *b) {
    return *(int *)a - *(int *)b;
}

void arrprint(int y, int x, int a[y][x]) {
    for (int i=0; i < y; i++) {
        for (int j=0; j < x; j++)
            printf("%3d ", a[i][j]);
        printf("\n");
    }
}

void arrcopy(int y, int x, int a[y][x], int b[y][x]) {
    for (int i=0; i < y; i++)
        for (int j=0; j < x; j++)
            b[i][j] = a[i][j];
}

void arrtrans(int y, int x, int a[y][x], int aT[x][y]) {
    for (int i=0; i < y; i++)
        for (int j=0; j < x; j++)
            aT[j][i] = a[i][j];
}

void arrsort(int n, int a[n]) {
    qsort(a, n, sizeof(int), numcmp);
}

void arrsortrows(int y, int x, int a[y][x]) {
    for (int i=0; i < y; i++)
        arrsort(x, a[i]);
}

void arrsortcolumns(int y, int x, int a[y][x]) {
    int aT[x][y];
    arrtrans(y, x, a, aT);
    arrsortrows(x, y, aT);
    arrtrans(x, y, aT, a);
}

---

Quote:

---

2. C treats a 2d-array as if it is actually a 1d-array where each element is itself a row

---

Not quite. C 2-d arrays (and in fact all multidimensional arrays) are flat, one-dimensional arrays. 2-d arrays can have their elements accessed with the formula X * Y + Z where X is a row, Y is the size of the row dimension, and Z is the column. The compiler simply does the math for you if you use array-style access. And you have to do some setup if you want array-style access for multidimensional dynamic arrays.

Quote:

---

Originally Posted by Adak

Welcome to the forum, Hufnagel! :cool:

What is the connection between the data? The first table seems to have each record with it's record fields across one row.

In the second program it's just data. What's the relationship between the two tables?

Could you show what output you're trying to get, from a 3 row example of the data and records? Your description doesn't make it clear to me.

Normally, if you want to show sorted output two or more different ways, you would either copy the original (to preserve the order it has), and then sort the duplicate table (or create a table of pointers, and sort "through" the pointers, or a separate index table).

Using a duplicate table is easiest, an index table is :cool: and perhaps easier, but using pointers is more fun.

We can help you with the sorting for sure, but I'm not clear what you want for your final output.

---

This is what I'm trying to display:

PHP Code:

---

The top 3 sales for Jan is
Ballpoint pen A 58
Note C 46
Note A 34
The top 3 sales for Feb is
[product name] [number sold]
and so on for every month... 


---

The other one would be like this:

PHP Code:

---

The top 3 products sold over the year are:
[product name] [total of numbers in column]
and so on for the latter 2... 


---

I made a little bit of progress before looking at the replies:
I was able to sort each row in an increasing order,
not quite there with adding the columns though

Code:

---

#include<stdio.h>

int main(){

        FILE *fp;
        char filename[]="sales.dat";
        int a[11] [12];
        char str[11] [50] = {"Note A", "Note B", "Note C", "Ballpoint pen A", "Ballpoint pen B", "Ballpoint pen C",
                                "Pencil", "Marker", "Pencil case", "Erase A", "Erase B"};
        int h, i, j, k, tmp, min, sum;

        if(!(fp=fopen(filename, "rb"))){
                printf("Can't open a file\n");
                return -1;
        }
        if(fread(a, sizeof(int), 132, fp)!=132){
                fclose(fp);
                printf("Can't read\n");
                return -1;
        }
        printf("Success to read!\n");
        fclose(fp);

        for(i=0;i<11;i++){
                for(j=0;j<12;j++){
                        printf("%5d", a[i] [j]);
                }
                printf("\n");
    }
   

        for(i=0;i<12;i++){
            sum+=a[0] [i];
        }
        printf("%d\n", sum);
   
   
    for(h=0;h<12;h++){
        for(i=0;i<10;i++){
            min = a[i] [h];
            k = i;
            for(j=i+1;j<11;j++){
                if(a[j] [h] < min){
                    min = a[j] [h];
                    k = j;
                }
            }
            tmp = a[i] [h];
            a[i] [h] = a[k] [h];
            a[k] [h] = tmp;
        }
    }

   
    for(i=0;i<11;i++){
        for(j=0;j<12;j++){
                        printf("%5d", a[i] [j]);
                }
                printf("\n");
    }

    for(i=0;i<11;i++){
        min = a[10] [i];
        k = i;
        for(j=i+1;j<12;j++){
            if(a[10] [j] < min){
                min = a[10] [j];
                k = j;
            }
        }
        tmp = a[10] [i];
        a[10] [i] = a[10] [k];
        a[10] [k] = tmp;
    }

    for(i=0;i<11;i++){
        for(j=0;j<12;j++){
                        printf("%5d", a[i] [j]);
                }
                printf("\n");
    }

   

}

---

I do understand your point in saving the original data table, and messing around with the copy instead of the original. I'm not sure in how to do that though.
Also, how would I make it so the months and product names would be included and move with the modifications? Is that something that I should do with the first program?

Your array as defined has only integers (the number of sales). To keep the other data together you should use a struct rather than array of ints. For example:

ProductEntry
month : string
product : string
sales : int

With a proper definition, we can simply change `int' to `ProductEntry' and the procedure works as before. Sort the array copy and then print the relevant result.

Code:

---

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

// ProductEntry
typedef struct {
    char month[4];
    char product[50];
    int sales;
} ProductEntry;

// Y: number of rows (products)
// X: number of cols (months)
#define Y 11
#define X 12

// Index->name mappings
const char PRODSTR[Y][50] = {"Note A", "Note B", "Note C", "Ballpoint pen A", "Ballpoint pen B", "Ballpoint pen C",
                                "Pencil", "Marker", "Pencil case", "Erase A", "Erase B"};
const char MONTHSTR[X][4] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

// Create an initialized ProductEntry data[][] by using an int numbers[][] as input
void ProductEntry_create(int y, int x, ProductEntry data[y][x], int numbers[y][x]);

// arrprint...(...) : array printing functions
void arrprintheader(void);
void arrprintall(int y, int x, ProductEntry a[y][x]);
void arrprintmonth3(int y, int x, ProductEntry a[y][x], int month_index);
void arrprintproduct3(int y, int x, ProductEntry a[y][x], int product_index);

// arrcopy(y, x, a, b): copy elements of a into b
// arrtrans(y, x, a, aT): transpose a into aT
void arrcopy(int y, int x, ProductEntry a[y][x], ProductEntry b[y][x]);
void arrtrans(int y, int x, ProductEntry a[y][x], ProductEntry aT[x][y]);

// arrsort, arrsortrows, arrsortcolumns: array sorting
void arrsort(int n, ProductEntry a[n]);
void arrsortrows(int y, int x, ProductEntry a[y][x]);
void arrsortcolumns(int y, int x, ProductEntry a[y][x]);

int main(int argc, char *argv[])
{
    int rawnumbers[Y] [X] = {
                        {34, 56, 27, 100, 74, 56, 12, 5, 87, 29, 63, 16},
                        {9, 11, 14, 55, 30, 4, 47, 150, 136, 26, 18, 12},
                        {46, 3, 22, 8, 78, 14, 52, 27, 35, 80, 123, 90},
                        {58, 38, 79, 120, 85, 52, 39, 23, 31, 10, 10, 46},
                        {8, 5, 3, 8, 2, 21, 7, 3, 8, 13, 8, 7},
                        {26, 32, 28, 26, 24, 20, 19, 22, 23, 28, 30, 29},
                        {12, 19, 54, 51, 41, 36, 20, 28, 3, 5, 7, 32},
                        {22, 14, 53, 21, 25, 23, 22, 180, 31, 6, 213, 58},
                        {10, 14, 43, 12, 13, 17, 14, 12, 11, 9, 54, 15},
                        {21, 20, 28, 17, 19, 14, 13, 12, 17, 18, 14, 11},
                        {24, 21, 13, 24, 20, 16, 13, 17, 24, 38, 23, 28} };
   
    // Initialize rawdata table
    ProductEntry rawdata[Y][X];
    ProductEntry_create(Y, X, rawdata, rawnumbers);
   
    printf("\nTop sales by month:\n");
    ProductEntry bymonth[Y][X];
    arrcopy(Y, X, rawdata, bymonth);
    arrsortcolumns(Y, X, bymonth);
    arrprintheader();
    for(int monthid=0; monthid <= X-1; monthid++)
        arrprintmonth3(Y, X, bymonth, monthid);
   
    printf("\nTop sales sorted by product:\n");
    ProductEntry byproduct[Y][X];
    arrcopy(Y, X, rawdata, byproduct);
    arrsortrows(Y, X, byproduct);
    arrprintheader();
    for (int prodid=0; prodid <= Y-1; prodid++)
        arrprintproduct3(Y, X, byproduct, prodid);
   
    return 0;
}

void ProductEntry_create(int y, int x, ProductEntry data[y][x], int numbers[y][x]) {
    for (int i=0; i < y; i++)
        for (int j=0; j < x; j++) {
            strcpy(data[i][j].month, MONTHSTR[j]);
            strcpy(data[i][j].product, PRODSTR[i]);
            data[i][j].sales = numbers[i][j];
        }
}

void arrprintheader(void) {
    printf("%-5s %-20s %-5s\n", "---", "-------------", "-----");
    printf("%-5s %-20s %-5s\n", "Mon", "Product name", "Sales");
    printf("%-5s %-20s %-5s\n", "---", "-------------", "-----");
}

void arrprintall(int y, int x, ProductEntry a[y][x]) {
    arrprintheader();
    for (int i=0; i < y; i++) {
        for (int j=0; j < x; j++) {
            printf("%-5s %-20s %-5d\n", a[i][j].month, a[i][j].product, a[i][j].sales);
        }
    }
}

void arrprintmonth3(int y, int x, ProductEntry a[y][x], int mo) {
    for (int i=0; i < 3; i++) {
        printf("%-5s %-20s %-5d\n", a[i][mo].month, a[i][mo].product, a[i][mo].sales);
    }
}

void arrprintproduct3(int y, int x, ProductEntry a[y][x], int pr) {
    for (int i=0; i < 3; i++) {
        printf("%-5s %-20s %-5d\n", a[pr][i].month, a[pr][i].product, a[pr][i].sales);
    }
}

void arrcopy(int y, int x, ProductEntry a[y][x], ProductEntry b[y][x]) {
    for (int i=0; i < y; i++)
        for (int j=0; j < x; j++)
            b[i][j] = a[i][j];
}

void arrtrans(int y, int x, ProductEntry a[y][x], ProductEntry aT[x][y]) {
    for (int i=0; i < y; i++)
        for (int j=0; j < x; j++)
            aT[j][i] = a[i][j];
}

static inline int ProductEntry_sort_desc(const void*a, const void *b) {
    const ProductEntry *x = a;
    const ProductEntry *y = b;
    return y->sales - x->sales;
}

void arrsort(int n, ProductEntry a[n]) {
    qsort(a, n, sizeof(a[0]), ProductEntry_sort_desc);
}

void arrsortrows(int y, int x, ProductEntry a[y][x]) {
    for (int i=0; i < y; i++)
        arrsort(x, a[i]);
}

void arrsortcolumns(int y, int x, ProductEntry a[y][x]) {
    ProductEntry aT[x][y];
    arrtrans(y, x, a, aT);
    arrsortrows(x, y, aT);
    arrtrans(x, y, aT, a);
}

---

This is a text file version of some of what you're doing, using structs.

Code:

---

/*Sorts, sums, and displays this data, by row and col
Item Name      Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
==================================================================
Notepad A,      34  56  27 100  74  56  12  5  87  29  63  16
Notepad B,        9  11  14  55  30  4  47 150 136  26  18  12
Notepad C,      46  3  22  8  78  14  52  27  35  80 123  90
Ballpoint pen A, 58  38  79 120  85  52  39  23  31  10  10  46
Ballpoint pen B,  8  5  38  22  1  7  3    8  1  3  8  7
Ballpoint pen C, 26  32  28  26  24  20  19  22  23  28  30  29
Pencil,          12  19  54  51  41  36  20  28  3  5  7  32
Marker,          22  14  53  21  25  23  22  180 31  6 213  58
Pencil case,    10  14  43  12  13  17  14  12  11  9  54  15
Eraser A,        21  20  28  17  19  14  13  12  17  18  14  11
Eraser B,        24  21  13  24  20  16  13  17  24  38  23  28
*/

#include <stdio.h>

#define SIZE 128

typedef struct {
  char name[20];
  int moAmt[12];
}Sales;

void sortRows(Sales *sales, int n);
void printIt(Sales *sales, int n);
void sum(Sales *sales, int n, char *header,int *sumrow,int *sumcol);

int main(void) {
  int i=0,j,n=0;
  char ch;
  char header[79]={"Item Name      Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec  Sum of Row\n"};
  int sumrow[11], sumcol[12];

  Sales sales[30];
  char line[SIZE];
  FILE *fp=fopen("salesData.txt","r");
  if(!fp){
      printf("Error, unable to open file\n");
      return 0;
  }
  while(fgets(line, SIZE, fp)) {
      //printf("%s\n",line);
     
      sscanf(line,"%[^','], %d %d %d %d %d %d %d %d %d %d %d %d*c",sales[i].name,
      &sales[i].moAmt[0],&sales[i].moAmt[1],&sales[i].moAmt[2],&sales[i].moAmt[3],
      &sales[i].moAmt[4],&sales[i].moAmt[5],&sales[i].moAmt[6],&sales[i].moAmt[7],
      &sales[i].moAmt[8],&sales[i].moAmt[9],&sales[i].moAmt[10],&sales[i].moAmt[11]),
      &ch;
     
      printf("%20s, ",sales[i].name);
      for(j=0;j<12;j++) {
        printf("%3d ",sales[i].moAmt[j]);
      }
      printf("\n");
      ++i;
  }
  fclose(fp);
  printf("i: %d\n",i);
  n=i;
  printf("\n\nBefore insertionSort\n\n");
  for(i=0;i<n;i++) {
      printf("%20s, ",sales[i].name);
      for(j=0;j<n;j++) {
        printf("%3d ",sales[i].moAmt[j]);
      }
      printf("\n"); 
  }
  sortRows(sales,i); //sort by first Month sales ascending
  printIt(sales,i);
  printf("\n\n");
 
  sum(sales,i,header,sumrow,sumcol );

/* 
  sortCols(sales, i);
  sumRows(sales, i);
  sumCols(sales, i);
*/

  printf("\n");
  return 0;
}
void sum(Sales *sales, int n,char *header,int *sumrow, int *sumcol) {
  int r,c;
 
  printf("    %s\n",header);
  printf("===============================================================================\n");
  for(r=0;r<n;r++) {
      printf("%19s ",sales[r].name);
      sumrow[r]=0;
      for(c=0;c<12;c++) {
        printf("%3d ",sales[r].moAmt[c]);
        sumrow[r]+=sales[r].moAmt[c];
      }
      printf("  %4d\n",sumrow[r]);
  }
  printf("===============================================================================\n");
  printf("                    ");
  for(c=0;c<12;c++) {
      sumcol[c]=0;
      for(r=0;r<n;r++) {
        sumcol[c]+=sales[r].moAmt[c];
      }
      printf("%3d ",sumcol[c]);
  }
}


void sortRows(Sales *sales, int n) {
  int i, j=0;
  Sales val;
  printf("Start: \n");
  for(i=1;i<n;i++) { 
      val = sales[i]; //sales[i].moAmt[0];
      j = i-1;
      while(sales[j].moAmt[0] > val.moAmt[0]) {
        sales[j+1] = sales[j];
        --j;
        if(j<0) break;
      } 
      sales[j+1] = val;
  }
}

/* sum() has the updated print out format. They'll be moved to this
function later.
*/
void printIt(Sales *sales, int n) {
  int i,j;
  printf("\n");
  for(i=0;i<n;i++) {
      printf("%19s, ",sales[i].name);
      for(j=0;j<12;j++) {
        printf("%3d ",sales[i].moAmt[j]);
      }
      printf("\n");
  }
  printf("\n");
}

---

After sum() it looks like this:
Attachment 12196