Answer to Question #223678 in C for Buzz

Question

1. Write a C program to add two matrix using functions & dynamic memory allocation. Also check for addition compatibility.



2. Write a C program to multiply two matrix using functions & dynamic memory

allocation. Also check for multiplication compatibility.

Answer 1

1.

#include <stdio.h>
int main() {
  int rows, column, a[100][100], b[100][100], sum[100][100], i, j;
  printf("Enter no. of rows: ");
  scanf("%d", &rows);
  printf("Enter no. of columns: ");
  scanf("%d", &column);


  printf("\nEnter elements of 1st matrix:\n");
  for (i = 0; i < rows; ++i)
    for (j = 0; j < column; ++j) {
      printf("Enter element a%d%d: ", i + 1, j + 1);
      scanf("%d", &a[i][j]);
    }


  printf("Enter elements of 2nd matrix:\n");
  for (i = 0; i < rows; ++i)
    for (j = 0; j < column; ++j) {
      printf("Enter element b%d%d: ", i + 1, j + 1);
      scanf("%d", &b[i][j]);
    }
  for (i = 0; i < rows; ++i)
    for (j = 0; j < column; ++j) {
      sum[i][j] = a[i][j] + b[i][j];
    }
  printf("\nSum of two matrices: \n");
  for (i = 0; i < rows; ++i)
    for (j = 0; j < column; ++j) {
      printf("%d   ", sum[i][j]);
      if (j == column - 1) {
        printf("\n\n");
      }
    }


  return 0;
}

2.

#include <stdio.h>


void enterData(int firstMatrix[][10], int secondMatrix[][10], int rowFirst, int columnFirst, int rowSecond, int columnSecond);
void multiplyMatrices(int firstMatrix[][10], int secondMatrix[][10], int multResult[][10], int rowFirst, int columnFirst, int rowSecond, int columnSecond);
void display(int mult[][10], int rowFirst, int columnSecond);


int main()
{
	int firstMatrix[10][10], secondMatrix[10][10], mult[10][10], rowFirst, columnFirst, rowSecond, columnSecond, i, j, k;


	printf("Enter rows and column for first matrix: ");
	scanf("%d %d", &rowFirst, &columnFirst);


	printf("Enter rows and column for second matrix: ");
	scanf("%d %d", &rowSecond, &columnSecond);


	// If colum of first matrix in not equal to row of second matrix, asking user to enter the size of matrix again.
	while (columnFirst != rowSecond)
	{
		printf("Error! column of first matrix not equal to row of second.\n");
		printf("Enter rows and column for first matrix: ");
		scanf("%d%d", &rowFirst, &columnFirst);
		printf("Enter rows and column for second matrix: ");
		scanf("%d%d", &rowSecond, &columnSecond);
	}


	// Function to take matrices data
        enterData(firstMatrix, secondMatrix, rowFirst, columnFirst, rowSecond, columnSecond);


        // Function to multiply two matrices.
        multiplyMatrices(firstMatrix, secondMatrix, mult, rowFirst, columnFirst, rowSecond, columnSecond);


        // Function to display resultant matrix after multiplication.
        display(mult, rowFirst, columnSecond);


	return 0;
}


void enterData(int firstMatrix[][10], int secondMatrix[][10], int rowFirst, int columnFirst, int rowSecond, int columnSecond)
{
	int i, j;
	printf("\nEnter elements of matrix 1:\n");
	for(i = 0; i < rowFirst; ++i)
	{
		for(j = 0; j < columnFirst; ++j)
		{
			printf("Enter elements a%d%d: ", i + 1, j + 1);
			scanf("%d", &firstMatrix[i][j]);
		}
	}


	printf("\nEnter elements of matrix 2:\n");
	for(i = 0; i < rowSecond; ++i)
	{
		for(j = 0; j < columnSecond; ++j)
		{
			printf("Enter elements b%d%d: ", i + 1, j + 1);
			scanf("%d", &secondMatrix[i][j]);
		}
	}
}


void multiplyMatrices(int firstMatrix[][10], int secondMatrix[][10], int mult[][10], int rowFirst, int columnFirst, int rowSecond, int columnSecond)
{
	int i, j, k;


	// Initializing elements of matrix mult to 0.
	for(i = 0; i < rowFirst; ++i)
	{
		for(j = 0; j < columnSecond; ++j)
		{
			mult[i][j] = 0;
		}
	}


	// Multiplying matrix firstMatrix and secondMatrix and storing in array mult.
	for(i = 0; i < rowFirst; ++i)
	{
		for(j = 0; j < columnSecond; ++j)
		{
			for(k=0; k<columnFirst; ++k)
			{
				mult[i][j] += firstMatrix[i][k] * secondMatrix[k][j];
			}
		}
	}
}


void display(int mult[][10], int rowFirst, int columnSecond)
{
	int i, j;
	printf("\nOutput Matrix:\n");
	for(i = 0; i < rowFirst; ++i)
	{
		for(j = 0; j < columnSecond; ++j)
		{
			printf("%d  ", mult[i][j]);
			if(j == columnSecond - 1)
				printf("\n\n");
		}
	}
}