Program to print Lower triangular and Upper triangular matrix of an array

25 Jun, 2022
Prerequisite – Multidimensional Arrays in C / C++Given a two dimensional array, Write a program to print lower triangular matrix and upper triangular matrix. 
Lower triangular matrix is a matrix which contains elements below principle diagonal including principle diagonal elements and rest of the elements are 0.
Upper triangular matrix is a matrix which contains elements above principle diagonal including principle diagonal elements and rest of the elements are 0.
LOWER TRIANGULAR : UPPER TRIANGULAR : 
Examples : 
Input : matrix[3][3] = {1 2 3
                       4 5 6
                       7 8 9}
Output :
Lower : 1 0 0        Upper : 1 2 3
        4 5 0                0 5 6
        7 8 9                0 0 9

Input : matrix[3][3] = {7 8 9
                        3 2 1
                        6 5 4}
Output :
Lower : 7 0 0       Upper : 7 8 9
        3 2 0               0 2 1
        6 5 4               0 0 4
Steps: 
For lower triangular matrix, we check the index position i and j i.e. row and column respectively. If column position is greater than row position we simply make that position 0.For upper triangular matrix, we check the index position i and j i.e. row and column respectively. If column position is smaller than row position we simply make that position 0.
For lower triangular matrix, we check the index position i and j i.e. row and column respectively. If column position is greater than row position we simply make that position 0.
For upper triangular matrix, we check the index position i and j i.e. row and column respectively. If column position is smaller than row position we simply make that position 0.
C++
C
Java
Python3
C#
PHP
Javascript
// C++ program to print Lower // triangular and Upper triangular// matrix of an array#include<iostream>  using namespace std;  // Function to form // lower triangular matrixvoid lower(int matrix[3][3], int row, int col){    int i, j;    for (i = 0; i < row; i++)    {        for (j = 0; j < col; j++)        {            if (i < j)            {                cout << "0" << " ";            }            else            cout << matrix[i][j] << " ";        }        cout << endl;    }}  // Function to form upper triangular matrixvoid upper(int matrix[3][3], int row, int col){    int i, j;          for (i = 0; i < row; i++)    {        for (j = 0; j < col; j++)        {            if (i > j)            {                cout << "0" << " ";            }            else            cout << matrix[i][j] << " ";        }        cout << endl;    }}  // Driver Codeint main(){    int matrix[3][3] = {{1, 2, 3},                         {4, 5, 6},                         {7, 8, 9}};    int row = 3, col = 3;          cout << "Lower triangular matrix: \n";    lower(matrix, row, col);          cout << "Upper triangular matrix: \n";    upper(matrix, row, col);              return 0;}
// C program to print lower triangular and upper triangular matrix#include <stdio.h>  // Function to print lower triangular matrixvoid lower (int a[3][3], int r, int c){  for(int i = 0; i < r; i++)  {    for(int j = 0; j < c; j++)    {      if(i > j)        printf("0");      else      printf("%d" , a[i][j]);      printf(" ");    }    printf("\n");  }}//Function to print upper triangular matrixvoid upper (int a[3][3], int r, int c){   for(int i = 0; i < r; i++)  {    for(int j = 0; j < c; j++)    {      if(i < j)        printf("0");      else      printf("%d" , a[i][j]);      printf(" ");    }    printf("\n");  }}int main() {    // code  int r = 3, c = 3;  int a[3][3] = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};     printf("\nLower Triangular Matrix is  :\n");  lower(a, r, c);  printf("\nUpper Triangular Matrix is  :\n");  upper(a, r, c);    return 0;}  // This code is contributed by aayushi2402.
// Java program to print Lower // triangular and Upper triangular// matrix of an arrayclass GFG{    // method to form lower     // triangular matrix    static void lower(int matrix[][],                       int row, int col)    {        int i, j;        for (i = 0; i < row; i++)        {            for (j = 0; j < col; j++)            {                if (i < j)                {                    System.out.print("0" + " ");                }                else                System.out.print(matrix[i][j] + " ");            }            System.out.println();        }    }          // Method to form upper    // triangular matrix    static void upper(int matrix[][],                       int row, int col)    {        int i, j;        for (i = 0; i < row; i++)        {            for (j = 0; j < col; j++)            {                if (i > j)                {                    System.out.print("0" + " ");                }                else                System.out.print(matrix[i][j] + " ");            }            System.out.println();        }    }           // Driver Code    public static void main(String args[])    {        int matrix[][] = {{1, 2, 3},                           {4, 5, 6},                           {7, 8, 9}};        int row = 3, col = 3;                  System.out.println("Lower triangular matrix: ");        lower(matrix, row, col);                  System.out.println("Upper triangular matrix: ");        upper(matrix, row, col);    }}
# Python3 program to print Lower # triangular and Upper triangular# matrix of an array  # Function to form lower triangular # matrixdef lower(matrix, row, col):            for i in range(0, row):              for j in range(0, col):                      if (i < j):                              print("0", end = " ");                          else:                print(matrix[i][j],                        end = " " );                  print(" ");      # Function to form upper triangular matrixdef upper(matrix, row, col):      for i in range(0, row):              for j in range(0, col):                      if (i > j):                print("0", end = " ");                          else:                print(matrix[i][j],                        end = " " );                  print(" ");  # Driver Codematrix = [[1, 2, 3],           [4, 5, 6],           [7, 8, 9]];row = 3;col = 3;      print("Lower triangular matrix: ");lower(matrix, row, col);      print("Upper triangular matrix: ");upper(matrix, row, col);          # This code is contributed by# Shivi_Aggarwal 
// C# program to print  // Lower triangular and// Upper triangular// matrix of an arrayusing System;  class GFG{    // method to form lower     // triangular matrix    static void lower(int [,]matrix,                       int row, int col)    {        int i, j;        for (i = 0; i < row; i++)        {            for (j = 0; j < col; j++)            {                if (i < j)                {                    Console.Write("0" + " ");                }                else                Console.Write(matrix[i, j] + " ");            }            Console.WriteLine();        }    }          // Method to form upper    // triangular matrix    static void upper(int [,]matrix,                       int row, int col)    {        int i, j;        for (i = 0; i < row; i++)        {            for (j = 0; j < col; j++)            {                if (i > j)                {                    Console.Write("0" + " ");                }                else                Console.Write(matrix[i, j] + " ");            }        Console.WriteLine();        }    }          // Driver Code    static public void Main ()    {        int [,]matrix = {{1, 2, 3},                         {4, 5, 6},                         {7, 8, 9}};        int row = 3, col = 3;                  Console.WriteLine("Lower triangular matrix: ");        lower(matrix, row, col);                  Console.WriteLine("Upper triangular matrix: ");        upper(matrix, row, col);    }}  // This code is contributed by ajit 
<?php// PHP program to print Lower // triangular and Upper triangular// matrix of an array  // Function to form // lower triangular matrixfunction lower($matrix, $row, $col){    $i; $j;    for ($i = 0; $i < $row; $i++)    {        for ($j = 0; $j < $col; $j++)        {            if ($i < $j)            {                echo "0" , " ";            }            else            echo $matrix[$i][$j] , " ";        }        echo "\n";    }}  // Function to form// upper triangular matrixfunction upper($matrix, $row, $col){    $i; $j;          for ($i = 0; $i < $row; $i++)    {        for ($j = 0; $j < $col; $j++)        {            if ($i > $j)            {                echo "0" , " ";            }            else            echo $matrix[$i][$j] ," ";        }    echo "\n";    }}  // Driver Code$matrix = array (array (1, 2, 3),                  array (4, 5, 6),                 array (7, 8, 9));$row = 3; $col = 3;  echo "Lower triangular matrix: \n";lower($matrix, $row, $col);  echo "Upper triangular matrix: \n";upper($matrix, $row, $col);      // This code is contributed by jit_t?>
<script>// Java  script program to print Lower// triangular and Upper triangular// matrix of an array      // method to form lower    // triangular matrix    function lower( matrix,row,col)    {        let i, j;        for (i = 0; i < row; i++)        {            for (j = 0; j < col; j++)            {                if (i < j)                {                    document.write("0" + " ");                }                else                document.write(matrix[i][j] + " ");            }            document.write("<br>");        }    }          // Method to form upper    // triangular matrix    function upper(matrix,row,col)    {        let i, j;        for (i = 0; i < row; i++)        {            for (j = 0; j < col; j++)            {                if (i > j)                {                    document.write("0" + " ");                }                else                document.write(matrix[i][j] + " ");            }            document.write("<br>");        }    }          // Driver Code              let matrix = [[1, 2, 3],                        [4, 5, 6],                        [7, 8, 9]];        let row = 3, col = 3;                  document.write("Lower triangular matrix: <br>");        lower(matrix, row, col);                  document.write("Upper triangular matrix: <br>");        upper(matrix, row, col);          // contributed by sravan kumar</script>
Output : 
Lower triangular matrix: 
1 0 0 
4 5 0 
7 8 9 
Upper triangular matrix: 
1 2 3 
0 5 6 
0 0 9 
Time Complexity: O(row x col)
Auxiliary Space: O(1)
This article is contributed by Rishabh Jain. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. 
jit_t
Shivi_Aggarwal
sravankumar8128
simmytarika5
sagar0719kumar
aayushi2402
_shinchancode
Matrix
School Programming
Matrix
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Matrix Chain Multiplication | DP-8
Program to find largest element in an array
Rat in a Maze | Backtracking-2
Sudoku | Backtracking-7
Find the number of islands | Set 1 (Using DFS)
Python Dictionary
Reverse a string in Java
Arrays in C/C++
Inheritance in C++
Interfaces in Java