A Number Pattern Program in C is a type of program that generates and displays a specific pattern of numbers based on user-defined input. These patterns can take various forms, such as triangles, squares, or pyramids, and are often used to demonstrate nested loops and formatting in C.

Example: Right-Angled Triangle Number Pattern

Let's explain a simple program that prints a right-angled triangle number pattern. For instance, if the user inputs the number 5, the output will look like this:

1
12
123
1234
12345

Logic of the Program:

1. Take an integer input from the user that represents the number of rows for the pattern.
2. Use a nested loop:
   • The outer loop will iterate through each row.
   • The inner loop will iterate through numbers from 1 to the current row number.
3. Print the numbers in the inner loop.
4. After each row, print a newline character to move to the next line.

C Program to Generate a Right-Angled Triangle Number Pattern:

#include <stdio.h>

int main() {
    int rows, i, j;

    // Input the number of rows from the user
    printf("Enter the number of rows: ");
    scanf("%d", &rows);

    // Generate the number pattern
    for (i = 1; i <= rows; i++) { // Outer loop for each row
        for (j = 1; j <= i; j++) { // Inner loop for numbers in each row
            printf("%d", j); // Print the number
        }
        printf("\n"); // Move to the next line after each row
    }

    return 0;
}

Explanation:

1. Variables:

   • int rows: Holds the number of rows for the pattern.
   • int i, j: Loop counters.

2. Input:

   • The program prompts the user to enter the number of rows for the pattern.

3. Outer Loop:

   • The outer loop (for (i = 1; i <= rows; i++)) controls the number of rows. It runs from 1 to rows.

4. Inner Loop:

   • The inner loop (for (j = 1; j <= i; j++)) controls the numbers printed on each row. It runs from 1 to i, ensuring that the number of printed digits increases with each row.

5. Printing:

   • Inside the inner loop, the program prints the current value of j.
   • After the inner loop, a newline (printf("\n")) is printed to move to the next row.

6. Output:

   • Finally, the program displays the number pattern based on the user's input.

Sample Output:

Example 1:

Enter the number of rows: 5
1
12
123
1234
12345

Example 2:

Enter the number of rows: 3
1
12
123

Key Points:

• Nested Loops: The program demonstrates the use of nested loops, which are essential for generating patterns.
• Dynamic Input: The number of rows can be changed by the user, making the program flexible.
• Simple Logic: The program has a straightforward logic that can be easily modified to create different patterns, such as pyramids, inverted triangles, etc.