Nested for Loops in Java

Chapter 10

Nested for Loops in Java

Class 10 - Logix Kips ICSE Computer Applications with BlueJ

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Java Program: Java Program to Display the Pattern

2 (ix). Write a program in Java to display the following patterns.

Java Program: Java Program to Display the Pattern

public class MirrorNumberPattern {
    public static void main(String[] args) {
 
        // Upper decreasing part
        for (int i = 5; i >= 1; i--) {
            for (int j = 1; j <= i; j++) {
                System.out.print(j + " ");
            }
            System.out.println();
        }
 
        // Lower increasing part
        for (int i = 2; i <= 5; i++) {
            for (int j = 1; j <= i; j++) {
                System.out.print(j + " ");
            }
            System.out.println();
        }
    }
}

1 2 3 4 5
1 2 3 4
1 2 3
1 2
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5

✅ Explanation

🔹 First Loop (Decreasing Pattern)

for (int i = 5; i >= 1; i--)

• Prints rows with numbers from 1 to i
• Creates the top inverted triangle

🔹 Second Loop (Increasing Pattern)

for (int i = 2; i <= 5; i++)

• Starts from 2 to avoid repeating the middle line
• Creates the bottom triangle

🔹 Inner Loop

for (int j = 1; j <= i; j++)

• Prints numbers starting from 1

✅ Key Concepts Used

✔ Nested for loops
✔ Pattern symmetry
✔ Loop control