Print Star Patterns (Triangle) in C, C++, Java & Python – Code with Explanation & Examples in Short and Simple

   

C Program

void triangle(int n) {
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++)
            printf("*");
        printf("\n");
    }
}

C Output

*
**
***
****

C++ Program

void triangle(int n) {
    for (int i = 1; i <= n; i++, cout << "\n")
        for (int j = 1; j <= i; j++) cout << "*";
}

C++ Output

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

JAVA Program

void triangle(int n) {
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++)
            System.out.print("*");
        System.out.println();
    }
}

JAVA Output

*
**
***

Python Program

def triangle(n):
    for i in range(1, n + 1):
        print('*' * i)

Python Output

*
**
***
****

In-Depth Explanation

Example

Let n = 4. The outer loop will execute 4 times (for 4 rows). For every row i, we will print i stars.

So:

Row 1 → 1 star → *

Row 2 → 2 stars → **

Row 3 → 3 stars → ***

Row 4 → 4 stars → ****

The number of stars increases with every row, creating a triangle aligned to the left.

Real-Life Analogy

Think of climbing stairs — each step is wider than the last. The pattern is like constructing steps or blocks on top of each other where each row holds more items than the one above it. Similarly, if you’re pouring water in levels or arranging tiles — the bottom always has more units than the top, building a triangle from the side.

Another example: Stack your books with one on the top row, two on the second, and so on. You’ll get a right-angled triangle structure.

Why It Matters

This triangle star pattern is one of the first exercises to understand how nested loops work:

The outer loop controls the number of lines

The inner loop controls the number of stars printed per line

It illustrates loop dependency — i.e., how the number of elements output is determined by the ongoing iteration of another loop.

Knowledge of this pattern aids in:

Loop range logic and control

Visualizing 2D issues

Creating symmetrical or growth-based patterns in UIs and games

What You'll Learn from This

Use of nested loops

Printing repeating characters using inner loops

General structure for all pattern types (this is the base)

Logic building: iterations and index values' influence on output

It also enhances your grip on output formatting, a significant aspect of creating command-line tools and visualizations.

Interview Relevance and Real Projects

This issue is extremely prevalent in programming interviews, particularly beginner and college-level coding phases.

Interviewers can pose:

Print triangle with numbers instead of stars

Print upside-down triangles

Print right-aligned triangles

In actual projects, this logic is implemented in:

CLI dashboards

Text games

Printing patterns

Terminal visualization tools

SEO-Optimized Explanation

Right-angled triangle star pattern is one of the basic programming problems to illustrate how students should manage nested loops and formatted output. Students learn how to print stars line by line and increment the number on each loop iteration, understanding how loops communicate with each other and how formatting of visual output can be controlled in languages like C, C++, Java, and Python. This triangle printing issue is the foundation for more complicated pattern programs such as pyramids, diamonds, and number pyramids. Star patterns practice develops logical thinking, reinforces fundamental syntax usage, and assists in preparation for technical interviews, school assignments, and competitive programming problems.