Напишите рекурсивную функцию sumrecursive (), чтобы найти сумму первых n натуральных чисел.

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Write a recursive function sumRecursive() to find the sum of first n natural numbers.

Let us say S(n) is sum of first n natural numbers. It can be defined as a mathematical recursive formula as follows:
S(n) = 1 if (n == 1) (Because 1 is the first natural number)
S(n) = n + S(n - 1) (Sum of first n natural numbers is n + Sum of first n - 1 natural numbers)

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Compilation Errors

warning in SumOfNaturalNum1.c, Line No : 1
 S(n) = n + S(n - 1);
 ^
 data definition has no type or storage class


warning in SumOfNaturalNum1.c, Line No : 1
 type defaults to 'int' in declaration of 'S' [-Wimplicit-int]


warning in SumOfNaturalNum1.c, Line No : 1
 parameter names (without types) in function declaration


Error in SumOfNaturalNum1.c, Line No : 1
 function 'S' is initialized like a variable


Error in SumOfNaturalNum1.c, Line No : 1
 S(n) = n + S(n - 1);
        ^

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Что я уже пробовал:

Correct/Complete the Code :

#include <stdio.h>
#include "SumOfNaturalNum1.c" //anyone please tell me the logic to write in "SumOfNaturalNum1.c"
void main() {
	int n;
	printf("Enter a natural number : ");
	scanf("%d",&n);
	if (n > 0)
		printf("The sum of first %d natural numbers : %d\n", n, sumRecursive(n));
	else
		printf("Invalid Number\n");
}

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