C++ Program to Print a 2D Array

Here we will see how to print a 2D array using a C++ program. Below are the examples:

Input: {{1, 2, 3},
           {4, 5, 6},
           {7, 8, 9}}
Output: 1 2 3 
              4 5 6
              7 8 9

Input: {{11, 12, 13},
            {14, 15, 16}}
Output: 11 12 13
              14 15 16

There are 2 ways to print a 2D array in C++:

1. Using for loop.
2. Using range-based for loop.

Let's start discussing each of these methods in detail.

1. Using for loop

The general method to print a 2D array using for loop requires two for loops to traverse all the rows and columns of the given 2D matrix and print the elements.

• The outer loop will loop from index 0 to row_length-1.
• It traverses the 2D array row-wise, therefore the first row is printed then it goes to print the second row.

Below is the C++ program to print a 2D array using for loop:

// C++ program to print 
// 2D array using for loop
#include <iostream>
using namespace std;

// Driver code
int main() 
{
  const int i = 3, j = 3;
  // Declaring array
  int arr[i][j] = {{1, 2, 3},
                   {4, 5, 6},
                   {7, 8, 9}};
  for(int a = 0; a < 3; a++)
  {
    for(int b = 0; b < 3; b++)
    {
      cout << arr[a][b] << " ";
    }
    cout << endl;
  }  
    return 0;
}

1 2 3 
4 5 6 
7 8 9 

Time Complexity: O(n*m) where n and m are dimensions of the array.
Auxiliary Space: O(1)

2. Using a Range-Based for loop

Instead of using for loop, this method will use a range-based for loop. Below is the C++ program to print a 2D array using a range-based for loop:

// C++ program to print 2D
// array using range-based for loop
#include <iostream>
using namespace std;

// Driver code
int main()
{
    const int i = 3, j = 3;
    int matrix[i][j] = {{1, 2, 3},
                        {4, 5, 6},
                        {7, 8, 9}};
    for (auto &row : matrix)
    {
        for (auto &column : row)
        {
            cout << column << " ";
        }
        cout << endl;
    }
}

1 2 3 
4 5 6 
7 8 9 

Time Complexity: O(n*m) where n and m are dimensions of the array.
Auxiliary Space: O(1)