# Print triangle patterns of stars in C and Java

Write a C and Java program to print triangle patterns of stars.

This post covers below patterns formed by right-angled triangle and its mirror –

##### Pattern 1: Right-angled Triangle

* *
* * *
* * * *
* * * * *

This is one of the most basic and easiest pattern. We can have n rows. 1st row will contain 1 star, 2nd row will contain 2 stars, and so on.. We can use two nested loops to print this pattern where outer loop represents row number (say i) and inner loop simply prints the star pattern i times.

## Java

##### Pattern 2: Mirror of Right-angled Triangle

*
*  *
*  *  *
*  *  *  *
*  *  *  *  *

Suppose we have n rows. Here, 1st row will contain (n-1) spaces followed by 1 star, 2nd row will contain (n-2) spaces followed by 2 stars, and so on.. We can use nested loops to print this pattern where outer loop represents row number (say i) and inner loop prints the space (n-i times) followed by the star pattern (i times).

## Java

##### Pattern 3: Hollow Right-angled Triangle

* *
*   *
*     *
* * * * *

The idea remains same as Pattern 1 but here we print ‘*’ only for last row and first & last positions for each row. For all other positions, we print space.

## Java

##### Pattern 4: Mirror of Hollow Right-angled Triangle

*
*  *
*     *
*        *
*  *  *  *  *

Here the idea remains the same as Pattern 2 but we print ‘*’ only for last row and first & last cell in each row. All other positions will be filled by spaces.