C Programming: Matrix Data Transfer and Calculations

Matrix Data Transfer Example

This section presents C code intended to transfer data between matrices based on region identifiers.

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

int main () {
    int a[64][4];
    int b[3][15];
    int i, region, sum_asup, sum_ahab, j;

    j = 0;
    region = 1;
    sum_asup = 0; // Initialize sums
    sum_ahab = 0; // Initialize sums

    // Assuming 'a' matrix is populated with data
    for (i = 0; i < 64; i++) { // Corrected loop condition
        if (a[i][0] == region) {
            sum_asup = sum_asup + a[i][2];
            sum_ahab = sum_ahab + a[i][3];
        }
        
        // Check if the next element belongs to a different region or if it's the end of the array
        if (i + 1 < 64 && a[i+1][0] != region) {
            b[0][j] = region;
            b[1][j] = sum_asup;
            b[2][j] = sum_ahab;
            j++;
            sum_asup = 0;
            sum_ahab = 0;
            region++;
        } else if (i + 1 == 64) { // Handle the last region if it ends exactly at the array boundary
            b[0][j] = region;
            b[1][j] = sum_asup;
            b[2][j] = sum_ahab;
            j++;
        }
    }
    
    // Handling the last element if it was part of the current region and the loop finished
    // Note: The logic above might need refinement based on exact requirements for the last entry.
    
    printf("Data transfer process completed. Check matrix b.\n");
    return 0;
}

3x3 Matrix: Sum and Difference Based on Position Parity

This C program prompts the user to enter 9 numbers into a 3x3 matrix. Numbers at positions where the sum of subscripts (i+j) is even are added to the result; those where the sum is odd are subtracted.

#include <stdio.h>
#include <conio.h> // For getch()

#define F 3
#define C 3

int main () {
    int a[F][C];
    int num, result = 0, i, j;

    printf("Enter 9 numbers for the 3x3 matrix:\n");

    for (i = 0; i < F; i++) { // Corrected loop condition
        for (j = 0; j < C; j++) { // Corrected loop condition
            printf ( "Enter number a[%d][%d]: ", i, j);
            if (scanf ( "%d", &num) != 1) { 
                // Handle input error if necessary
                return 1;
            }
            a[i][j] = num;

            // Position parity check: 0 is considered even
            if ((i + j) % 2 == 0) {
                result = result + num;
            } else {
                result = result - num;
            }
        }
    }

    printf ( "\nResult (Even positions added, Odd positions subtracted) is: %d\n", result);
    printf ( "Press any key to continue...\n");
    getch ();
    return 0;
}

4x4 Matrix Calculations

This program handles a 4x4 matrix, calculating the sums of:

• The main diagonal.
• The secondary diagonal.
• The first and last rows combined.
• The first and last columns combined.

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

int main (void) {
    int matr[4][4];
    int suma_dp = 0; // Sum of main diagonal
    int suma_ds = 0; // Sum of secondary diagonal
    int suma_pu_f = 0; // Sum of first and last row
    int suma_pu_c = 0; // Sum of first and last column

    printf("Enter 16 numbers for the 4x4 matrix:\n");

    // Input Matrix
    for (int i = 0; i < 4; i++) {
        for (int j = 0; j < 4; j++) { // Corrected loop condition
            printf ( "Enter number matr[%d][%d]: ", i, j);
            if (scanf ( "%d", &matr[i][j]) != 1) {
                return 1;
            }
        }
    }

    // Calculations
    for (int l = 0; l < 4; l++) {
        // a. Main diagonal (i == j)
        suma_dp += matr[l][l];
        
        // b. Secondary Diagonal (i + j == 3)
        suma_ds += matr[l][3 - l];
        
        // c. First row (l) and Last row (3)
        suma_pu_f += matr[0][l]; // First row
        suma_pu_f += matr[3][l]; // Last row
        
        // d. First column (l) and Last column (3)
        suma_pu_c += matr[l][0]; // First column
        suma_pu_c += matr[l][3]; // Last column
    }

    printf ( "\nSum of the main diagonal: %d\n", suma_dp);
    printf ( "Sum of the secondary diagonal: %d\n", suma_ds);
    printf ( "Sum of the first and last row: %d\n", suma_pu_f);
    printf ( "Sum of the first and last column: %d\n", suma_pu_c);
    
    printf ( "Press Enter to exit...\n");
    system ( "pause");
    return 0;
}