用矩阵的下对角元素交换上对角元素的程序。

给定一个方阵，将矩阵的上对角元素与矩阵的下对角元素交换。
例子 ：

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

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

Input:   1  2  3 
         4  5  6
         7  8  9

Output:  1  4  7
         2  5  8
         3  6  9

以下是上述想法的实现：

C++

// CPP Program to implement matrix
// for swapping the upper diagonal
// elements with lower diagonal
// elements of matrix.
#include 
#define n 4
using namespace std;
 
// Function to swap the diagonal
// elements in a matrix.
void swapUpperToLower(int arr[n][n])
{
    // Loop for swap the elements of matrix.
    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            int temp = arr[i][j];
            arr[i][j] = arr[j][i];
            arr[j][i] = temp;
        }
    }
     
    // Loop for print the matrix elements.
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++)
            cout << arr[i][j] << " ";
        cout << endl;
    }
}
 
// Driver function to run the program
int main()
{
    int arr[n][n] = { { 2, 3, 5, 6 },
                    { 4, 5, 7, 9 },
                    { 8, 6, 4, 9 },
                    { 1, 3, 5, 6 } };
 
    // Function call
    swapUpperToLower(arr);
    return 0;
}
 
}

Java

// java Program to implement matrix
// for swapping the upper diagonal
// elements with lower diagonal
// elements of matrix.
import java.io.*;
 
class GFG
{
    static int n = 4;
     
    // Function to swap the diagonal
    // elements in a matrix.
    static void swapUpperToLower(int arr[][])
    {
        // Loop for swap the elements of matrix.
        for (int i = 0; i < n; i++)
        {
            for (int j = i + 1; j < n; j++)
            {
                int temp = arr[i][j];
                arr[i][j] = arr[j][i];
                arr[j][i] = temp;
            }
        }
         
        // Loop for print the matrix elements.
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < n; j++)
                System.out.print( arr[i][j] +" ");
                System.out.println();
        }
         
    }
     
    // Driver code
    public static void main (String[] args)
    {
        int arr[][] = { { 2, 3, 5, 6 },
                        { 4, 5, 7, 9 },
                        { 8, 6, 4, 9 },
                        { 1, 3, 5, 6 } };
 
        // Function call
        swapUpperToLower(arr);
             
    }
}
 
// This code is contributed by vt_m.

Python 3

# Python Program to implement matrix
# for swapping the upper diagonal
# elements with lower diagonal
# elements of matrix.
 
# Function to swap the diagonal
# elements in a matrix.
def swapUpperToLower(arr):
    n = 4;
     
    # Loop for swap the elements
    # of matrix.
    for i in range(0, n):
        for j in range(i + 1, n):
            temp = arr[i][j];
            arr[i][j] = arr[j][i];
            arr[j][i] = temp;
         
    # Loop for print the matrix elements.
    for i in range(0, n):
        for j in range(0, n):
            print(arr[i][j], end = " ");
        print(" ");
     
# Driver Code
 
arr = [[2, 3, 5, 6 ],[ 4, 5, 7, 9 ],
       [8, 6, 4, 9 ],[ 1, 3, 5, 6 ]];
 
# Function call
swapUpperToLower(arr);
 
# This code is contributed
# by Shivi_Aggarwal

C#

// C# Program to implement matrix
// for swapping the upper diagonal
// elements with lower diagonal
// elements of matrix.
using System;
 
class GFG
{
    static int n = 4;
     
    // Function to swap the diagonal
    // elements in a matrix.
    static void swapUpperToLower(int [,]arr)
    {
        // Loop for swap the elements of matrix.
        for (int i = 0; i < n; i++)
        {
            for (int j = i + 1; j < n; j++)
            {
                int temp = arr[i, j];
                arr[i, j] = arr[j, i];
                arr[j, i] = temp;
            }
        }
         
        // Loop for print the matrix elements.
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < n; j++)
                Console.Write(arr[i, j] +" ");
                Console.WriteLine();
        }
         
    }
     
    // Driver code
    public static void Main ()
    {
        int [,]arr = {{ 2, 3, 5, 6 },
                      { 4, 5, 7, 9 },
                      { 8, 6, 4, 9 },
                      { 1, 3, 5, 6 }};
 
        // Function call
        swapUpperToLower(arr);
             
    }
}
 
// This code is contributed by vt_m.

Javascript

// JavaScript Program to implement matrix
// for swapping the upper diagonal
// elements with lower diagonal
// elements of matrix.
var arr = [ [ 2, 3, 5, 6 ],
                    [ 4, 5, 7, 9 ],
                    [ 8, 6, 4, 9 ],
                    [ 1, 3, 5, 6 ]
                ];
 var n = arr.length;
  
    // Loop for swap the elements of matrix.
    for (var i = 0; i < n; i++)
    {
        for ( var j = i + 1; j < n; j++)
        {
             var temp = arr[i][j];
            arr[i][j] = arr[j][i];
            arr[j][i] = temp;
        }
    }
     
    // Loop for print the matrix elements.
    for (var i = 0; i < n; i++) {
        for ( var j = 0; j < n; j++)
            {
                document.write( arr[i][j] + " ");
            }
        document.write("<br>");
    }
 
// This code is contributed by SoumikMondal

Javascript

// java script Program to implement matrix
// for swapping the upper diagonal
// elements with lower diagonal
// elements of matrix.
 
    let n = 4;
     
    // Function to swap the diagonal
    // elements in a matrix.
    function swapUpperToLower(arr)
    {
        // Loop for swap the elements of matrix.
        for (let i = 0; i < n; i++)
        {
            for (let j = i + 1; j < n; j++)
            {
                let temp = arr[i][j];
                arr[i][j] = arr[j][i];
                arr[j][i] = temp;
            }
        }
         
        // Loop for print the matrix elements.
        for (let i = 0; i < n; i++)
        {
            for (let j = 0; j < n; j++)
                document.write( arr[i][j] +" ");
                document.write("<br>");
        }
         
    }
     
    // Driver code
     
        let arr = [[2, 3, 5, 6 ],
                        [ 4, 5, 7, 9 ],
                        [ 8, 6, 4, 9 ],
                        [ 1, 3, 5, 6 ]];
 
        // Function call
        swapUpperToLower(arr);
         
// contributed by sravan kumar

输出 ：

2 4 8 1 
3 5 6 3 
5 7 4 5 
6 9 9 6 

时间复杂度： O(N ² )

辅助空间： O(1)