How to print the numbers in different formats using C program?

In C programming, we can print numbers and symbols in different patterns like pyramids and triangles using nested loops. The outer loop controls the rows while inner loops handle spacing and pattern generation.

Syntax

for(int i = 1; i <= rows; i++) {
    // Outer loop for rows
    for(int j = 1; j <= columns; j++) {
        // Inner loop for columns/pattern
        printf("pattern");
    }
    printf("
");
}

Example 1: Star Pyramid Pattern

This program creates a pyramid using stars with proper spacing −

#include <stdio.h>

int main() {
    int n;
    printf("Enter number of lines: ");
    scanf("%d", &n);
    printf("
");
    
    // Loop for each row
    for(int i = 1; i <= n; i++) {
        // Print leading spaces
        for(int space = 0; space <= n - i; space++) {
            printf(" ");
        }
        // Print stars
        for(int j = 1; j <= i * 2 - 1; j++) {
            printf("*");
        }
        printf("
");
    }
    return 0;
}

Enter number of lines: 5

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

Example 2: Number Right Triangle

This program displays numbers in a right-angled triangle pattern −

#include <stdio.h>

int main() {
    int i, j, rows;
    printf("Input number of rows: ");
    scanf("%d", &rows);
    
    for(i = 1; i <= rows; i++) {
        for(j = 1; j <= i; j++) {
            printf("%d ", j);
        }
        printf("
");
    }
    return 0;
}

Input number of rows: 6
1 
1 2 
1 2 3 
1 2 3 4 
1 2 3 4 5 
1 2 3 4 5 6 

Example 3: Inverted Number Triangle

This program creates an inverted triangle pattern with numbers −

#include <stdio.h>

int main() {
    int i, j, rows;
    printf("Input number of rows: ");
    scanf("%d", &rows);
    
    for(i = rows; i >= 1; i--) {
        for(j = 1; j <= i; j++) {
            printf("%d ", j);
        }
        printf("
");
    }
    return 0;
}

Input number of rows: 5
1 2 3 4 5 
1 2 3 4 
1 2 3 
1 2 
1 

Key Points

• Use nested loops where outer loop controls rows and inner loops control columns and spacing.
• For pyramids, calculate spaces as (total_rows - current_row) and stars as (2 * current_row - 1).
• Always use proper spacing and formatting for clear pattern display.

Conclusion

Number and symbol patterns in C are created using nested for loops. The key is understanding how to control spacing, repetition, and formatting to achieve the desired visual output.