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Recap - Sigma Function

Part of the Fundamentals section of Coddy's Java journey — lesson 55 of 73.

Challenge

Easy

Write a function named sigma with one argument that represents a number n.

The function will return the sum of all the numbers from 1 to n (including).

For example, for sigma(5), the function will return 15, because 15 = 1 + 2 + 3 + 4 + 5.

Try it yourself

import java.util.Scanner;

public class Main {
    public static int sigma(int n) {
        // Write your code below
    }
    
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int res = sigma(n);
        System.out.println(res);
    }
}

All lessons in Fundamentals

1Introduction

Java Hello World!Comments Basic Program Structure

4Operators Part 1

Arithmetic Operators Modulo Operator Increment/Decrement Post Increment/Decrement Arithmetic Shortcuts Comparison Operators String Comparison

7Basic IO

System.out Methods Formatting Output Scanner Class Recap - Till 120 Recap - True or False

10Methods (Functions)

Declaring Methods Method Parameters Return Types Method OverloadingRecap - Sigma FunctionRecap - Validation Function Void Methods

13String Operations

String Methods Part 1 String Methods Part 2 String Formatting String Comparison

2Variables Part 1

Numbers String Boolean char Type Declaration

5Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3 Logical Operators Part 4

8Calculator App

Welcome Message Getting Numbers

Project lesson

Basic Operations

Project lesson

Formatted Output

Project lesson

11Arrays Basics

Declaring Arrays Accessing Elements Modifying Arrays Array Methods Recap - Product Array Recap - Reversed Array

14Final Challenges

Number Pattern Pattern Finder Student Grade Calculator

3Variables Part 2

Constants Naming Conventions Recap - Initialize Variables Type Casting Part 1 Type Casting Part 2

6Decision Making

If Statement If - Else Switch Statement Ternary Operator Recap - If Else Nested If - Else

9Loops

For Loop Part 1 While Loop Do While Loop Break Continue For Loop Part 2 Nested Loop Infinite Loop Recap - Dynamic Input

12Iterating Over Arrays

Using For Loop Enhanced For Loop Common Array Operations