Sum of matrices#9536

Sum of matrices (Editorial)

Given matrices $А$ and $В$ , compute their sum — the matrix $С$ , where

С_{ij} = A_{ij} + B_{ij}

С_{ij} = A_{ij} + B_{ij}

Algorithm implementation

Declare the matrices $a, b$ and $c$ .

#define MAX 101
int a[MAX][MAX], b[MAX][MAX], c[MAX][MAX];

Read the input data — matrices $А$ and $В$ .

scanf("%d %d", &n, &m);
for (i = 0; i < n; i++)
for (j = 0; j < m; j++)
  scanf("%d", &a[i][j]);

for (i = 0; i < n; i++)
for (j = 0; j < m; j++)
  scanf("%d", &b[i][j]);

C++

Compute the sum of the matrices: $C = A + B$ C = A + B.

for (i = 0; i < n; i++)
for (j = 0; j < m; j++)
  c[i][j] = a[i][j] + b[i][j];

Print the resulting matrix.

for (i = 0; i < n; i++)
{
  for (j = 0; j < m; j++)
    printf("%d ", c[i][j]);
  printf("\n");
}

Algorithm implementation – double pointer

Declare the matrices $a$ , $b$ and $c$ as double pointers.

int **a, **b, **c;

The function Read reads the matrix $ma t r$ .

void Read(int **&matr, int n, int m)
{
  matr = new int* [n];
  for (i = 0; i < n; i++)
  {
    matr[i] = new int[m];
    for (j = 0; j < m; j++)
      scanf("%d", &matr[i][j]);
  }
}

C++

The function Sum computes the sum of the matrices $A + B$ A + B and stores it in matrix $C$ .

void Sum(int **a, int **b, int **&c, int n, int m)
{
  c = new int* [n];
  for (i = 0; i < n; i++)
  {
    c[i] = new int[m];
    for (j = 0; j < m; j++)
       c[i][j] = a[i][j] + b[i][j];
  }
}

C++

The function Print prints matrix $A$ .

void Print(int **a)
{
  for (i = 0; i < n; i++)
  {
    for (j = 0; j < m; j++)
      printf("%d ", a[i][j]);
    printf("\n");
  }
}

C++

The main part of the program. Read the dimensions of the matrices $n$ and $m$ .

scanf("%d %d", &n, &m);

Read the matrices $a$ and $b$ .

Read(a, n, m);
Read(b, n, m);

Compute the sum of the matrices $C = A + B$ C = A + B.

Sum(a, b, c, n, m);

Print the resulting matrix.

Print(c);