045.2_varun_practice_sheet_question_2.c

// 2) a) Given an (n x n) matrix, find the sum of the squares of the diagonal elements.

// Value of n: 3
// 1 2 3
// 3 4 5
// 5 6 7
// 66

/*
#include <stdio.h>
#include <math.h>

int main() {
  int num_of_r_c;

  printf("Enter the number of rows and columns in an nxn matrix: ");
  scanf("%i", &num_of_r_c);
  printf("\n");

  int matrix[num_of_r_c][num_of_r_c];
  int sum = 0;

  for (int row_count = 0; row_count < num_of_r_c; row_count++) {
    for (int column_count = 0; column_count < num_of_r_c; column_count++) {
      printf("Enter the value of %dx%d: ", row_count + 1, column_count + 1);
      scanf("%i", &matrix[row_count][column_count]);

      sum += (row_count == column_count) ? pow(matrix[row_count][column_count], 2) : 0;
    }
  }

  printf("\n");

  printf("Your matrix is: \n");
  for (int row_count = 0; row_count < num_of_r_c; row_count++) {
    for (int column_count = 0; column_count < num_of_r_c; column_count++) {
      printf("%3i  ", matrix[row_count][column_count]);
    }
    printf("\n");
  }

  printf("\n");

  printf("Sum of diagonal elements is: %i \n", sum);
}
*/

// 2) b) Given an (n x m) matrix, find the matrix obtained by multiplying it with its transpose.

// Value of n: 2
// Value of m: 3
// 1 2 3
// 4 5 6
// 14 32
// 32 77

/*
#include <stdio.h>

int main() {
  int num_of_r;
  int num_of_c;

  printf("Enter the number of rows in an mxn matrix: ");
  scanf("%i", &num_of_r);
  printf("Enter the number of columns in an mxn matrix: ");
  scanf("%i", &num_of_c);
  printf("\n");

  int matrix[num_of_r][num_of_c];
  int matrix_transpose[num_of_c][num_of_r];
  int matrix_product[num_of_r][num_of_r];

  for (int row_count = 0; row_count < num_of_r; row_count++) {
    for (int column_count = 0; column_count < num_of_c; column_count++) {
      printf("Enter the value of %dx%d: ", row_count + 1, column_count + 1);
      scanf("%i", &matrix[row_count][column_count]);
      matrix_transpose[column_count][row_count] = matrix[row_count][column_count];
    }
  }

  printf("\n");
  printf("Your %dx%d matrix is: \n", num_of_r, num_of_c);
  for (int row_count = 0; row_count < num_of_r; row_count++) {
    for (int column_count = 0; column_count < num_of_c; column_count++) {
      printf("%3i  ", matrix[row_count][column_count]);
    }
    printf("\n");
  }

  printf("\n");
  printf("Your %dx%d matrix's %dx%d transpose is: \n", num_of_r, num_of_c, num_of_c, num_of_r);
  for (int row_count = 0; row_count < num_of_c; row_count++) {
    for (int column_count = 0; column_count < num_of_r; column_count++) {
      printf("%3i  ", matrix_transpose[row_count][column_count]);
    }
    printf("\n");
  }

  // multiplying matrix and matrix_transpose
  for (int row_count = 0; row_count < num_of_r; row_count++) {
    for (int column_count = 0; column_count < num_of_r; column_count++) {
      matrix_product[row_count][column_count] = 0;
      for (int index = 0; index < num_of_c; index++) {
        matrix_product[row_count][column_count] += matrix[row_count][index] * matrix_transpose[index][column_count];
      }
    }
  }

  printf("\n");

  printf("Your multiplied %dx%d matrix is: \n", num_of_r, num_of_r);
  for (int row_count = 0; row_count < num_of_r; row_count++) {
    for (int column_count = 0; column_count < num_of_r; column_count++) {
      printf("%3i  ", matrix_product[row_count][column_count]);
    }
    printf("\n");
  }
}
*/

// 2) c) Given a (n x m) matrix, find a sub-matrix with a given required sum.

// Value of n: 3
// Value of m: 4
// Required sum: 30
// 1 2 3 4
// 3 4 5 6
// 5 6 7 8

// 3 4 5
// 5 6 7

#include <stdio.h>

int main() {
  int num_of_r;
  int num_of_c;
  int sum;

  printf("Enter the number of rows in an mxn matrix: ");
  scanf("%i", &num_of_r);
  printf("Enter the number of columns in an mxn matrix: ");
  scanf("%i", &num_of_c);
  printf("Enter the required sum: ");
  scanf("%i", &sum);
  printf("\n");

  int matrix[num_of_r][num_of_c];

  for (int row_count = 0; row_count < num_of_r; row_count++) {
    for (int column_count = 0; column_count < num_of_c; column_count++) {
      printf("Enter the value of %dx%d: ", row_count + 1, column_count + 1);
      scanf("%i", &matrix[row_count][column_count]);
    }
  }

  printf("\n");

  printf("Your matrix is: \n");
  for (int row_count = 0; row_count < num_of_r_c; row_count++) {
    for (int column_count = 0; column_count < num_of_r_c; column_count++) {
      printf("%3i  ", matrix[row_count][column_count]);
    }
    printf("\n");
  }
}