Program to print elements of a Matrix row-wise skipping alternate elements

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Given a matrix of N*N size where N is always odd, the task is to print elements of a matrix row-wise skipping alternate elements.

Examples:

Input: mat[3][3] = 
{{1, 4, 3},
 {2, 5, 6},
 {7, 8, 9}}
Output: 1 3 5 7 9

Input: mat[5][5] = 
{{1, 2, 3, 4, 9},
 {5, 6, 7, 8, 44},
 {19, 10, 11, 12, 33},
 {13, 14, 15, 16, 55},
 {77, 88, 99, 111, 444}}
Output: 1 3 9 6 8 19 11 33 14 16 77 99 444

Approach:

Start traversing the matrix.
For each row, check if the row number is even or odd.
- If the row is even, then print the elements at the even index of that row.
- If the row is odd, print the elements at the odd index of that row.

Implementation:

C++

// C++ program to print elements of a Matrix 
// row-wise skipping alternate elements
#include <bits/stdc++.h>
using namespace std;
#define R 100
#define C 100
 
// Function to print the alternate
// elements of a matrix
void printElements(int mat[][C], int n)
{
    for (int i = 0; i < n; i++) {
        if (i % 2 == 0)
            for (int j = 0; j < n; j += 2)
                cout << mat[i][j] << " ";
        else
            for (int j = 1; j < n; j += 2)
                cout << mat[i][j] << " ";
    }
}
 
// Driver code
int main()
{
    int n = 3;
    int mat[R][C] = { { 1, 5, 3 },
                      { 2, 4, 7 },
                      { 9, 8, 6 } };
 
    printElements(mat, n);
 
    return 0;
}

Java

// Java Program to print elements of a Matrix
// row-wise skipping alternate elements
import java.util.*;
import java.lang.*;
 
class GFG{
// Function to print the alternate
// elements of a matrix
static void printElements(int[][] mat, int n)
{
    for (int i = 0; i < n; i++) 
    {
        if (i % 2 == 0)
            for (int j = 0; j < n; j += 2)
                System.out.print(mat[i][j] + " ");
        else
            for (int j = 1; j < n; j += 2)
                System.out.print(mat[i][j] + " ");
    }
}
 
// Driver code
public static void main(String args[])
{
    int n = 3;
    int[][] mat = new int[][]{ { 1, 5, 3 },{ 2, 4, 7 },{ 9, 8, 6 } };
 
    printElements(mat, n);
}
}
 
// This code is contributed 
// by Akanksha Rai(Abby_akku)

Python3

# Python 3 program to print elements of a Matrix
# row-wise skipping alternate elements  
 
# Function to print the alternate
# elements of a matrix
def printElements(mat, n) :
 
    for i in range(n) :
        if i % 2 == 0 :
            for j in range(0, n, 2) :
                print(mat[i][j],end = " ")
        else :
            for j in range(1, n, 2) :
                print(mat[i][j],end =" ")
             
     
# Driver Code
if __name__ == "__main__" :
 
    n = 3
    mat = [ [ 1, 5, 3],
            [ 2, 4, 7],
            [ 9, 8, 6] ]
 
    printElements(mat , n)
 
 
# This code is contributed by ANKITRAI1

C#

// C# Program to print elements 
// of a Matrix row-wise skipping 
// alternate elements
using System;
 
class GFG
{
// Function to print the alternate
// elements of a matrix
static void printElements(int[,] mat, 
                          int n)
{
    for (int i = 0; i < n; i++) 
    {
        if (i % 2 == 0)
            for (int j = 0; j < n; j += 2)
                Console.Write(mat[i, j] + " ");
        else
            for (int j = 1; j < n; j += 2)
                Console.Write(mat[i, j] + " ");
    }
}
 
// Driver code
public static void Main()
{
    int n = 3;
    int[,] mat = new int[,]{ { 1, 5, 3 }, 
                             { 2, 4, 7 },
                             { 9, 8, 6 }};
 
    printElements(mat, n);
}
}
 
// This code is contributed 
// by ChitraNayal

PHP

<?php
// PHP program to print elements of a Matrix
// row-wise skipping alternate elements
 
// Function to print the alternate
// elements of a matrix
function printElements(&$mat, $n)
{
    for ($i = 0; $i < $n; $i++)
    {
        if ($i % 2 == 0)
            for ($j = 0; $j < $n; $j += 2)
            {
                echo $mat[$i][$j] ;
                echo " ";
            } 
        else
            for ($j = 1; $j < $n; $j += 2)
            {
                echo $mat[$i][$j] ;
                echo " ";
            }
    }
}
 
// Driver code
$n = 3;
$arr = array(array(1, 2, 4), 
             array(5, 6, 8)); 
$mat = array(array(1, 5, 3),
             array(2, 4, 7),
             array(9, 8, 6));
 
printElements($mat, $n);
 
// This code is contributed 
// by Shivi_Aggarwal
?>

Javascript

<script>
// javascript Program to print elements of a Matrix
// row-wise skipping alternate elements
 
    // Function to print the alternate
    // elements of a matrix
    function printElements(mat , n) {
        for (i = 0; i < n; i++) {
            if (i % 2 == 0)
                for (j = 0; j < n; j += 2)
                    document.write(mat[i][j] + " ");
            else
                for (j = 1; j < n; j += 2)
                    document.write(mat[i][j] + " ");
        }
    }
 
    // Driver code
     
        var n = 3;
        var mat =[[ 1, 5, 3 ], 
        [2, 4, 7 ], [
        9, 8, 6 ] ];
 
        printElements(mat, n);
 
// This code contributed by umadevi9616
</script>

Output

1 3 4 9 6

Time complexity: O(n²)
Auxiliary space: O(1)

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