使用递归的自然数之和

给定数字n，请找到前n个自然数的总和。要计算总和，我们将使用递归函数recur_sum()。
例子 ：

Input : 3
Output : 6
Explanation : 1 + 2 + 3 = 6

Input : 5
Output : 15
Explanation : 1 + 2 + 3 + 4 + 5 = 15

以下是使用递归找到不超过n的自然数之和的代码：

C++

// C++ program to find the
// sum of natural numbers up
// to n using recursion
#include 
using namespace std;
 
// Returns sum of first
// n natural numbers
int recurSum(int n)
{
    if (n <= 1)
        return n;
    return n + recurSum(n - 1);
}
 
// Driver code
int main()
{
    int n = 5;
    cout << recurSum(n);
    return 0;
}

Java

// Java program to find the
// sum of natural numbers up
// to n using recursion
import java.util.*;
import java.lang.*;
 
class GFG
{
 
    // Returns sum of first
    // n natural numbers
    public static int recurSum(int n)
    {
        if (n <= 1)
            return n;
        return n + recurSum(n - 1);
    }
     
    // Driver code
    public static void main(String args[])
    {
        int n = 5;
        System.out.println(recurSum(n));
    }
}
 
// This code is contributed by Sachin Bisht

Python

# Python code to find sum
# of natural numbers upto
# n using recursion
 
# Returns sum of first
# n natural numbers
def recurSum(n):
    if n <= 1:
        return n
    return n + recurSum(n - 1)
 
# Driver code
n = 5
print(recurSum(n))

C#

// C# program to find the
// sum of natural numbers
// up to n using recursion
using System;
 
class GFG
{
 
    // Returns sum of first
    // n natural numbers
    public static int recurSum(int n)
    {
        if (n <= 1)
            return n;
        return n + recurSum(n - 1);
    }
     
    // Driver code
    public static void Main()
    {
        int n = 5;
        Console.WriteLine(recurSum(n));
    }
}
 
// This code is contributed by vt_m

Javascript

 
// JavaScript program to find the
// sum of natural numbers
// up to n using recursion
 
// Returns sum of first
// n natural numbers
function recurSum(n)
{
    if (n <= 1)
        return n;
    return n + recurSum(n - 1);
}
 
// Driver code
let n = 5;
document.write(recurSum(n));
 
// This code is contributed by mohan
 

输出 ：

15