📜  使用递归的自然数之和

📅  最后修改于: 2021-04-24 14:45:18             🧑  作者: Mango

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


PHP


Javascript


输出 :

15