Program for incrementing/decrementing triangle pattern

Namachila November 18, 2025

0 0 6 minutes read

Numeric incrementing triangle pattern:

Write a program to print a Numeric incrementing triangle pattern starting with a given number N.

Examples:

Below is the implementation:

C++

#include <iostream> 
using namespace std; 
int main() 
{ 
    int i, j, r, N, count; 
    N = 3; // initializing N 
    N--; 
    r = 5; 
    for (i = 0; i < r; i++) { 
        if (i <= r / 2) { 
            count = N + 1; 
            for (j = 0; j <= i; j++) { 
                N++; 
                cout << N << " "; 
            } 
            cout << endl; 
        } 
        else { 
            N = count - (r - i); 
            count = N; 
            for (j = i; j < r; j++) { 
                cout << N << " "; 
                N++; 
            } 
            cout << endl; 
        } 
    } 
} 

Java

// Java Program for incrementing 
// or decrementing triangle pattern 
import java.io.*; 
  
class GFG 
{ 
public static void main(String args[]) 
{ 
    int i, j, r, N, count = 0; 
    N = 3; // initializing N 
    N--; 
    r = 5; 
    for (i = 0; i < r; i++) 
    { 
        if (i <= r / 2)  
        { 
            count = N + 1; 
            for (j = 0; j <= i; j++)  
            { 
                N++; 
                System.out.print(N + " "); 
            } 
            System.out.println(); 
        } 
        else 
        { 
            N = count - (r - i); 
            count = N; 
            for (j = i; j < r; j++)  
            { 
                System.out.print(N + " "); 
                N++; 
            } 
            System.out.println(); 
        } 
    } 
} 
} 
  
// This code is contributed 
// by Subhadeep Gupta 

Python 3

# python 3 program to print incrementing  
# and decrementing triangle pattern 
if __name__ == "__main__": 
  
    N = 3 # initializing N 
    N -= 1
    r = 5
    for i in range( r): 
        if i <= r // 2: 
            count = N + 1
            for j in range(i + 1): 
                N += 1
                print(str(N), end = " ") 
              
            print() 
          
        else : 
            N = count - (r - i) 
            count = N 
            for j in range(i, r): 
                print(str(N), end = " ") 
                N += 1
              
            print() 
  
# This code is contributed 
# by ChitraNayal 

C#

// C# Program for incrementing 
// or decrementing triangle pattern 
using System;  
  
class GFG 
{ 
public static void Main() 
{ 
    int i, j, r, N, count = 0; 
    N = 3; // initializing N 
    N--; 
    r = 5; 
    for (i = 0; i < r; i++) 
    { 
        if (i <= r / 2)  
        { 
            count = N + 1; 
            for (j = 0; j <= i; j++)  
            { 
                N++; 
                Console.Write(N + " "); 
            } 
            Console.Write("\n"); 
        } 
        else
        { 
            N = count - (r - i); 
            count = N; 
            for (j = i; j < r; j++)  
            { 
                Console.Write(N + " "); 
                N++; 
            } 
            Console.Write("\n"); 
        } 
    } 
} 
} 
  
// This code is contributed  
// by ChitraNayal 

PHP

<?php 
// PHP program for incrementing 
// or decrementing triangle pattern 
$N = 3; // initializing N 
$N--; 
$r = 5; 
for ($i = 0; $i < $r; $i++) 
{ 
if ($i <= $r / 2) 
{ 
    $count = $N + 1; 
    for ($j = 0; $j <= $i; $j++) 
    { 
        $N++; 
        echo $N . " "; 
    } 
    echo "\n"; 
} 
else
{ 
    $N = $count - ($r - $i); 
    $count = $N; 
    for ($j = $i; $j < $r; $j++)  
    { 
        echo $N . " "; 
        $N++; 
    } 
    echo "\n"; 
} 
} 
  
// This code is contributed 
// by ChitraNayal 
?> 

Javascript

<script> 
      var i, j, r, N, count; 
      N = 3; // initializing N 
      N--; 
      r = 5; 
      for (i = 0; i < r; i++) { 
        if (i <= r / 2) { 
          count = N + 1; 
          for (j = 0; j <= i; j++) { 
            N++; 
            document.write(N + "  "); 
          } 
          document.write("<br>"); 
        } else { 
          N = count - (r - i); 
          count = N; 
          for (j = i; j < r; j++) { 
            document.write(N + "  "); 
            N++; 
          } 
          document.write("<br>"); 
        } 
      } 
    </script>

Output

Time Complexity: O(r²)
Auxiliary Space: O(1)

Numeric decrementing triangle pattern:

Write a program to print a Numeric decrementing triangle pattern starting with a given number N.