Java Program to Find the Trace of a Matrix

Write a Java program to find the trace of a matrix using for loop. The trace of a matrix is the sum of its diagonal. In this Java example, we use nested for loop to iterate matrix rows and columns. Next, if(i == j) checks whether it’s a diagonal element and adds that item to trace.

package NumPrograms;

import java.util.Scanner;

public class MatrixTrace1 {
	
	private static Scanner sc;	
	
	public static void main(String[] args) {
		
		int i, j, rows, columns, trace = 0;	
		sc= new Scanner(System.in);	
		
		System.out.print("Enter Matrix Rows and Columns =  ");
		rows = sc.nextInt();
		columns = sc.nextInt();
		
		int[][] Tra_arr = new int[rows][columns];
		
		System.out.println("Please Enter the Matrix Items =  ");
		for(i = 0; i < rows; i++) 
		{
			for(j = 0; j < columns; j++) 
			{
				Tra_arr[i][j] = sc.nextInt();
			}		
		}
		
		for(i = 0; i < rows; i++) 
		{
			for(j = 0; j < columns; j++) 
			{
				if(i == j)
				{
					trace = trace + Tra_arr[i][j];
				}
			}		
		}
		
		System.out.println("\nThe Trace Of the Matrix = " + trace);

	}
}
Java Program to Find the Trace of a Matrix

Java program to find the trace of a matrix using a while loop

package NumPrograms;

import java.util.Scanner;

public class MatrixTrace2 {
	private static Scanner sc;	
	public static void main(String[] args) {
		
		int i, j, rows, columns, trace = 0;	
		sc= new Scanner(System.in);	
		
		System.out.print("Enter Matrix Rows and Columns =  ");
		rows = sc.nextInt();
		columns = sc.nextInt();
		
		int[][] Tra_arr = new int[rows][columns];
		
		System.out.println("Please Enter the Matrix Items =  ");
		i = 0; 
		while(i < rows) 
		{
			j = 0; 
			while(j < columns) 
			{
				Tra_arr[i][j] = sc.nextInt();
				j++;
			}	
			i++;
		}
		
		i = 0; 
		while(i < rows) 
		{
			j = 0; 
			while(j < columns) 
			{
				if(i == j)
				{
					trace = trace + Tra_arr[i][j];
				}
				j++;
			}	
			i++;
		}
		
		System.out.println("\nThe Trace Of the Matrix = " + trace);

	}
}
Enter Matrix Rows and Columns =  3 3
Please Enter the Matrix Items =  
10 20 30
40 50 60
70 80 125

The Trace Of the Matrix = 185

This Java example uses the do while loop to calculate and print the trace of a given matrix.

package NumPrograms;

import java.util.Scanner;

public class MatrixTrace3 {
	private static Scanner sc;	
	public static void main(String[] args) {
		
		int i, j, rows, columns, trace = 0;	
		sc= new Scanner(System.in);	
		
		System.out.print("Enter Matrix Rows and Columns =  ");
		rows = sc.nextInt();
		columns = sc.nextInt();
		
		int[][] Tra_arr = new int[rows][columns];
		
		System.out.println("Please Enter the Matrix Items =  ");
		i = 0; 
		do 
		{
			j = 0; 
			do 
			{
				Tra_arr[i][j] = sc.nextInt();
				if(i == j) 
				{
					trace = trace + Tra_arr[i][j];
				}
			}while(++j < columns);	
		}while(++i < rows);
		
		System.out.println("\nThe Trace Of the Matrix = " + trace);

	}
}
Enter Matrix Rows and Columns =  3 3
Please Enter the Matrix Items =  
19 22 45
77 88 125
13 50 500

The Trace Of the Matrix = 607

About Suresh

Suresh is the founder of TutorialGateway and a freelance software developer. He specialized in Designing and Developing Windows and Web applications. The experience he gained in Programming and BI integration, and reporting tools translates into this blog. You can find him on Facebook or Twitter.