Question

How to sum 2D array (matrix) in C++

Answer 1

#include <iostream>

using std::cout;
using std::endl;


int sum_matrix(int matrix[][5])
{
	int sum = 0;

	for (int i = 0; i < 3; i++) {
		for (int j = 0; j < 5; j++)
			sum += matrix[i][j];
	}
	return sum;
}

int main()
{
	int matrix[3][5] = { { 12, 43, 65, 10, 12 },
	                     { 33, 42, 98, 80, 50 },
	                     { 88, 77, 99, 100, 9843 } };


	cout << sum_matrix(matrix) << endl;

	return 0;
}


/*
run:

10652

*/

 

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Answer 2

#include <iostream>

using std::cout;
using std::endl;

int sum_matrix(int matrix[][5], int rows, int cols)
{
	int sum = 0;

	for (int i = 0; i < rows; i++) {
		for (int j = 0; j < cols; j++)
			sum += matrix[i][j];
	}
	return sum;
}

int main()
{
	int matrix[][5] = { { 12, 43, 65, 10, 12 },
	                    { 33, 42, 98, 80, 50 },
	                    { 88, 77, 99, 100, 9843 } };

	int rows = sizeof matrix / sizeof matrix[0];
	int cols = sizeof matrix[0] / sizeof(int);

	cout << sum_matrix(matrix, rows, cols) << endl;

	return 0;
}


/*
run:

10652

*/

 

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