Write a C program using dynamic memory allocation to subtract two matrices?

Answer 1

The easiest way would be to write a function that accepts two arrays and returns one.

Lets say you are working with two 2-dimensional arrays.

array<int,2>^ SubtractMatrices(int arr1[][2], int arr2[][2]);

void main()

{

int arr1[2][2] = {0,1,2,3};

int arr2[2][2] = {0,1,2,4};

array<int,2>^ newarr;

// array<int^,2>^ newarr[2][2] = SubtractMatrices(arr1, arr2);

}

array<int,2>^ SubtractMatrices(int arr1[][2], int arr2[][2])

{

array<int,2>^ newarr;

//Insert subtraction algorithm here

return newarr;

}

In this scenario you must pass the function 2 matrices, and then return a pointer to a new matrix.

Hmm, still seems to be an error in there with the return type. I'm not sure if that's the correct way to do it, I did this in Visual Studio's managed C++. .

Answer 2

#include
#include


void main()
{
int a[20][20],b[20][20],c[20][20],i,j,r1,r2,c1,c2,ta,tb;
clrscr();
printf("Enter order of Matrix A: ");
scanf("%d%d",&r1,&c1);
ta=r1*c1;
printf("\nEnter %d elements=",ta);
for(i=0;i{
for(j=0;jscanf("%d",&a[i][j]);
}
printf("\nEnter order of Matrix B: ");
scanf("%d%d",&r2,&c2);
tb=r2*c2;
if(r1==r2 && c1==c2)
{
printf("\nEnter %d elements=",tb);
for(i=0;i{
for(j=0;jscanf("%d",&b[i][j]);
}
for(i=0;i{
for(j=0;jc[i][j]=a[i][j]-b[i][j];
}
printf("\nSubtraction of matrix is\n");
for(i=0;i{
for(j=0;j{
printf("%d\t",c[i][j]);
}
printf("\n");
}
}
else
printf("\nSubraction is not possible pls enter same order");
getch();
}

Answer 3

#include <iostream>

#include <iomanip>

using namespace std;

int ** CreateMatrix( const int & rows, const int & cols )

{

int ** Matrix = ( int ** ) calloc( rows, sizeof( int * ));

for( int row=0; row<rows; ++row )

Matrix[row] = ( int * ) calloc( cols, sizeof( int ));

return( Matrix );

}

void DestroyMatrix( int ** Matrix, const int & rows, const int & cols )

{

for( int row=0; row<rows; ++row )

free( Matrix[row] );

free( Matrix );

}

void PrintMatrix( int ** Matrix, const int & rows, const int & cols )

{

for( int row=0; row<rows; ++row )

{

for( int col=0; col<cols; ++col )

cout << setw(6) << Matrix[row][col];

cout << endl;;

}

cout << endl;

}

int main()

{

// Seed random number generator.

srand(( unsigned int ) time( NULL ));

// Randomly set rows and columns for two-dimensional arrays (2-10 elements each).

int rows = rand() % 9 + 2;

int cols = rand() % 9 + 2;

// Instantiate two-dimensional arrays of int.

int ** Matrix1 = CreateMatrix(rows, cols);

int ** Matrix2 = CreateMatrix(rows, cols);

// Initialise arrays with random values (1 to 99).

for( int row=0; row<rows; ++row )

for( int col=0; col<cols; ++col )

{

Matrix1[row][col] = rand() % 99 + 1;

Matrix2[row][col] = rand() % 99 + 1;

}

// Print matrices.

PrintMatrix( Matrix1, rows, cols );

cout << "minus" << endl << endl;

PrintMatrix( Matrix2, rows, cols );

// Instantiate and initialise the result matrix.

int ** Result = CreateMatrix(rows, cols);

for( int row=0; row<rows; ++row )

for( int col=0; col<cols; ++col )

Result[row][col] = Matrix1[row][col] - Matrix2[row][col];

// Print result.

cout << "equals" << endl << endl;

PrintMatrix( Result, rows, cols );

// Release the arrays.

DestroyMatrix( Result, rows, cols );

DestroyMatrix( Matrix2, rows, cols );

DestroyMatrix( Matrix1, rows, cols );

Result = NULL;

Matrix2 = NULL;

Matrix1 = NULL;

return( 0 );

}