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 contain elements below principle diagonal including principle diagonal elements and rest of the elements are 0.
- Upper triangular matrix is a matrix which contain elements above principle diagonal including principle diagonal elements and rest of the elements are 0.
LOWER TRIANGULAR :
UPPER TIRANGULAR :
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.
C++
// C++ program to print Lower // triangular and Upper triangular // matrix of an array #include<iostream> using namespace std; // Function to form // lower triangular matrix void 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 marix void 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 Code int 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; } |
Java
// Java program to print Lower // triangular and Upper triangular // matrix of an array 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) { 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
# Python3 program to print Lower # triangular and Upper triangular # matrix of an array # Function to form lower triangular # matrix def 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 marix def 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 Code matrix = [[ 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#
// C# program to print // Lower triangular and // Upper triangular // matrix of an array using 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 // PHP program to print Lower // triangular and Upper triangular // matrix of an array // Function to form // lower triangular matrix function 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 marix function 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 ?> |
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
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