📅 Date: Feb 3, 2026
🔥 Topic: Nested Loops & Basic Patterns

🎨 Why Draw with Code?

Pattern printing isn't just about making pretty shapes. It is the best way to master Nested Loops.
The Golden Rule:
1. Outer Loop (i) controls the Rows.
2. Inner Loop (j) controls the Columns.

1️⃣ Square Pattern (The Warmup)

Simple N x N grid of stars.

****
****
****
****
    
for(int i=0; i<n; i++) {
    for(int j=0; j<n; j++) {
        cout << "*";
    }
    cout << endl;
}

2️⃣ Right Angled Triangle

Here, the number of stars equals the row number.

*
**
***
****
    
for(int i=1; i<=n; i++) {
    // Inner loop runs 'i' times
    for(int j=1; j<=i; j++) {
        cout << "*";
    }
    cout << endl;
}

3️⃣ Number Triangle

Instead of stars, we print the column number.

1
12
123
1234
    
for(int i=1; i<=n; i++) {
    for(int j=1; j<=i; j++) {
        cout << j;
    }
    cout << endl;
}

4️⃣ Floyd's Triangle (Flooding Numbers)

We keep a counter variable that keeps increasing.

1
2 3
4 5 6
7 8 9 10
    
int count = 1;
for(int i=1; i<=n; i++) {
    for(int j=1; j<=i; j++) {
        cout << count << " ";
        count++;
    }
    cout << endl;
}

💭 Thoughts

The key is finding the relationship between i and j. Once you crack the formula, the code writes itself.