Java Program to Print the Multiplication Table in a Triangle Form

In this form, a table is displayed row and column-wise, in such a way such that in every row, only the entries up to the same column number filled.

Example:

Input : rows = 6
Output:
    1
    2 4
    3 6 9
    4 8 12 16
    5 10 15 20 25
    6 12 18 24 30 36  

Approach: The idea is to use nested loops. First, display the column numbers. Then, use a nested loop to fill out the entries of the row.

1. In function main(), firstly the number of lines n is entered.
2. The loop for(i=0; i<rows; i++) is used to print the column number lines.
3. The loop for(i=0; i<rows; i++), is used to print the n rows entries. 4. The nested loop for(j = 0; j<=i; j++), is used to print the current entry.

Below is the implementation of the above approach.

1 
2 4 
3 6 9 
4 8 12 16 
5 10 15 20 25 
6 12 18 24 30 36 

Time Complexity: O(n²), where n is a number of rows.

Auxiliary Space: O(1) since using only constant variables