Floyd Triangle in C, C++, Java & Python – Code with Explanation & Examples in Short and Simple

   

C Program

#include <stdio.h>
int main(){
    int n=5,k=1;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=i;j++) printf("%d ",k++);
        printf("\n");
    }
}

C Output

Input:  
n = 5 

Output:  
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15

C++ Program

#include <iostream>
using namespace std;
int main(){
    int n=4,k=1;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=i;j++) cout<<k++<<" ";
        cout<<"\n";
    }
}

C++ Output

Input:  
n = 4  

Output:  
1
2 3
4 5 6
7 8 9 10

JAVA Program

public class Main{
    public static void main(String[] args){
        int n=6,k=1;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=i;j++) System.out.print(k+++" ");
            System.out.println();
        }
    }
}

JAVA Output

Input:  
n = 6  

Output:  
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
16 17 18 19 20 21

Python Program

n=3;k=1
for i in range(1,n+1):
    for j in range(i):
        print(k,end=" ");k+=1
    print()

Python Output

Input:  
n = 3 

Output:  
1
2 3
4 5 6

Deep-Dive Explanation

What is Floyd's Triangle?

Floyd's Triangle is a basic mathematical sequence that places consecutive natural numbers in a triangular shape. It's named after Robert Floyd, who employed it to demonstrate algorithms.

Step-by-Step Logic

Begin with a counter k = 1.

Outer loop iterates n rows.

Inner loop iterates i times (same as the row number).

Print k and increment k after every print.

Go to the next line after the end of each row.

Example for n = 5

Row 1 → 1

Row 2 → 2 3

Row 3 → 4 5 6

Row 4 → 7 8 9 10

Row 5 → 11 12 13 14 15

Why It's Useful in Learning

Teaches nested loops

Reinforces loop control and incrementing variables

Helps in pattern printing, which is common in interviews

Encourages mathematical thinking

Real-Life Analogy

Pretend to have a seating plan in a triangular shape where every seat is numbered consecutively from front to rear.

Uses

Number placement questions

Memory representation of triangular arrays

Pattern creation in the printing program

Interview Tip

Interviewers sometimes even ask you to create Floyd's Triangle in reverse, or starting from a number, which is an extension of this simple version.