C++ Program For Row Wise Sorting in 2D Array

Last Updated : 27 Jan, 2023

Given a 2D array, sort each row of this array and print the result.
Examples:

Input:
77 11 22 3
11 89 1 12
32 11 56 7
11 22 44 33
Output:
3 11 22 77
1 11 12 89
7 11 32 56
11 22 33 44

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

Method 1 (Using Bubble Sort):
Start iterating through each row of the given 2D array, and sort elements of each row using an efficient sorting algorithm.

C++

// C++ program to sort 
// 2D matrix row-wise
#include<bits/stdc++.h>
using namespace std;

void sortRowWise(int m[][4],
                 int r, int c)
{
  // Loop for rows of matrix
  for (int i = 0; i < r; i++) 
  {
    // Loop for column of matrix
    for (int j = 0; j < c; j++) 
    {
      // Loop for comparison and swapping
      for (int k = 0; k < c - j - 1; k++) 
      {
        if (m[i][k] > m[i][k + 1]) 
        {
          // Swapping of elements
          swap(m[i][k], m[i][k + 1]);
        }
      }
    }
  }

  // Printing the sorted matrix
  for (int i = 0; i < r; i++) 
  {
    for (int j = 0; j < c; j++)
      cout << m[i][j] << " ";
    cout << endl;
  }
}

// Driver code
int main()
{
  int m[][4] = {{9, 8, 7, 1},
                {7, 3, 0, 2},
                {9, 5, 3, 2},
                {6, 3, 1, 2}};
  int c = sizeof(m[0]) / sizeof(m[0][0]);
  int r = sizeof(m) / sizeof(m[0]);
  sortRowWise(m, r, c);
  return 0;
}

Output

Time complexity: O(r*c*c).
Auxiliary Space: O(1)

Method 2 (Using Library Function):
The idea is to use Arrays.sort() for every row of the matrix.

C++

// C++ program to sort 2D 
// matrix row-wise
#include <bits/stdc++.h>
using namespace std;
#define M 4
#define N 4

int sortRowWise(int m[M][N])
{
  // One by one sort 
  // individual rows.
  for (int i = 0; i < M; i++)
    sort(m[i], m[i] + N);

  // Printing the sorted matrix
  for (int i = 0; i < M; i++) 
  {
    for (int j = 0; j < N; j++)
      cout << (m[i][j]) << " ";
    cout << endl;
  }
}

// Driver code
int main()
{
  int m[M][N] = {{9, 8, 7, 1},
                 {7, 3, 0, 2},
                 {9, 5, 3, 2},
                 {6, 3, 1, 2}};
  sortRowWise(m);
}

Output:

Time complexity: O(N*M).
Auxiliary Space: O(1)

Sorting 2D Vector in C++ | Set 2 (In descending order by row and column)

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C++ Program For Row Wise Sorting in 2D Array

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