Print 2D arrays (matrix) in C++

This post will discuss how to print two-dimensional arrays (i.e., matrix) in C++.

A simple solution is to iterate over each row and column of the matrix using a simple for-loop and print each element. The following C++ program demonstrates it:

#include <iostream>

using namespace std;

int main()

{

const int m = 3, n = 3;

int mat[m][n] = {

{1, 2, 3},

{4, 5, 6},

{7, 8, 9}

};

for (int i = 0; i < m; i++) {

for (int j = 0; j < n; j++) {

std::cout << mat[i][j] << ' ';

}

std::cout << std::endl;

}

return 0;

}

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Output:

1 2 3
4 5 6
7 8 9

Here’s an equivalent version using a range-based for-loop. This can be used starting with C++ 11.

#include <iostream>

#include <algorithm>

using namespace std;

int main()

{

const int m = 3, n = 3;

int mat[m][n] = {

{1, 2, 3},

{4, 5, 6},

{7, 8, 9}

};

for (auto &row: mat) {

for (auto &i: row) {

std::cout << i << ' ';

}

std::cout << std::endl;

}

return 0;

}

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Output:

1 2 3
4 5 6
7 8 9

We can also create a template that deduces the size of the array from its declared type.

#include <iostream>

using namespace std;

template<typename T, size_t N, size_t M>

void printArray(T(&mat)[N][M])

{

for (int i = 0; i < N; i ++ ) {

for (int j = 0; j < M; j++ ) {

cout << mat[i][j] << ' ';

}

std::cout << std::endl;

}

int main()

{

const int m = 3, n = 3;

int mat[m][n] = {

{1, 2, 3},

{4, 5, 6},

{7, 8, 9}

};

printArray(mat);

return 0;

}

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Output:

1 2 3
4 5 6
7 8 9

That’s all about printing two-dimensional arrays in C++.

Print 2D arrays (matrix) in C++

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