Java Program to Print Right Triangle Star Pattern.

Right Triangle Star Pattern in Java

In this article we are going to see how to print the right triangle star program.

Example-1
When row value=4
*
* *
* * *
* * * *
* * * * *

Example-2:
When row value=5
*
* *
* * *
* * * *
* * * * *
* * * * * *

Now, let’s see the actual program to print it.

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Approach:

Enter total row and store it in an integer variable row.
Take first for loop to print all rows.
Take second/inner for loop to print column values.
Then go on printing the star symbols according to the iteration.

Method-1 : Static Star Symbol

import java.util.*;
class Main
{
 public static void main(String args[])
 { 
     // taking variable for loop iteration and row .
    int row,r,c;
    //creating object 
    Scanner s = new Scanner(System.in);
    // entering the number of row
    System.out.print("Enter rows : ");
    row = s.nextInt();
    // iteration for no. of row 
    for(r=1;r<=row;r++)
     {
         //iteration for printing stars
         for(c=1;c<=r;c++)
         {
             System.out.print("* ");
         }
         //taking to the new line 
         System.out.println(" ");
     } 
 }
}

Output:

Enter rows : 5
*  
* *  
* * *  
* * * *  
* * * * *

Method-2 : User Input Symbol

import java.util.*;
class Main
{
 public static void main(String args[])
 { 
     // taking variable for loop iteration and row .
    int row,r,c;
    //creating object 
    Scanner s = new Scanner(System.in);
    // entering the number of row
    System.out.print("Enter rows : ");
    row = s.nextInt();
    // enter symbol
    System.out.print("Enter symbol : ");
    char symbol = s.next().charAt(0);  
    
    // iteration for no. of row 
    for(r=1;r<=row;r++)
     {
         //iteration for printing stars
         for(c=1;c<=r;c++)
         {
             System.out.print(symbol);
         }
         //taking to the new line 
         System.out.println(" ");
     } 
 }
}

Output:
Enter rows : 5
Enter symbol : #
#
# #
# # #
# # # #
# # # # #

Explanation :

Let’s understand the program by going through the detailed explanation.

We have taken row value as 5.

Iteration-1
r=1 (passes the first for loop condition) because it will execute until r<=row
Now r=1 so inner for loop will execute 1 time because it will execute until c<=r
Star will be printed one time because inner for loop will be executed only once.

Iteration-2
r=2 (passes the first for loop condition) because it will execute until r<=row
Now r=2 so inner for loop will execute 2 times because it will execute until c<=r
Star will be printed two times because inner for loop will be executed two times..

* *

Iteration-3
r=3 (passes the first for loop condition) because it will execute until r<=row
Now r=3 so inner for loop will execute 3 times because it will execute until c<=r
Star will be printed three times because inner for loop will be executed three times.

* * *

Iteration-4

r=4 (passes the first for loop condition) because it will execute until r<=row
Now r=4 so inner for loop will execute 4 times because it will execute until c<=r
Star will be printed three times because inner for loop will be executed four times.

* * * *

Iteration-5

r=5 (passes the first for loop condition) because it will execute until r<=row
Now r=5 so inner for loop will execute 5 times because it will execute until c<=r
Star will be printed five times because inner for loop will be executed five times.

* * * * *

Now i=6, so first for loop condition will fail. So next for loop will not be executed any more.

Now, after end of all iteration we will see the complete pattern is printed on the output screen like this.

* 
* *  
* * *  
* * * *  
* * * * *

C Code:

#include <stdio.h> 
int main() 
{ 
    int row,r,c; 
    printf("Enter rows : "); 
    scanf("%d",&row); 
    for(r=1;r<=row;r++) 
    { 
        for(int c=1;c<=r;c++) 
        { 
            printf("* "); 
            
        } 
        printf("\n"); 
        
    } 
    return 0; 
}

Output: 

Enter rows : 5
* 
* * 
* * * 
* * * * 
* * * * *

C++ Code:

#include <iostream> 
using namespace std; 
int main() 
{ 
    int row,r,c; 
    cout << "Enter rows : "; 
    cin >> row; 
    for(r = 1; r <= row; r++) 
    { 
        for(c = 1; c <= r; c++) 
        { 
            cout << "* "; 
            
        } 
        cout << "\n"; 
        
    } 
    return 0; 
}

Output:

Enter rows : 5
* 
* * 
* * * 
* * * * 
* * * * *

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