Give a recursive definition for finding the sum of the first n odd positive inte

Question

Give a recursive definition for finding the sum of the first n odd positive integers. For example: If n = 1, then the output should be 1. If n = 2, then the output should be 4 (= 1 + 3). If n = 3, then the output should be 9 (= 1+ 3 + 5). Use the Three-Question Approach to verify your definition in the task above: The Base-Case Question: Is there a non-recursive way out of the algorithm, and does the algorithm work correctly for this base case? The Smaller-Caller Question: Does each recursive call to the algorithm involve a smaller case of the original problem, leading inescapably to the base case? The General-Case Question: Assuming the recursive call(s) to the smaller case(s) works correctly, does the algorithm work correctly for the general case? Implement the recursive function. Your code should meet the following requirements: The code should prompt the user for a valid input. Check if the input value is valid or not. For an invalid input, reject the input and prompt the user again for a valid one. The code should print changes of the input value while executing itself. The final output (the sum of the first n odd positive integers) should be printed along with intermediate output values (sums of the first n-1, n-2, n-3... odd integers).

Explanation / Answer

#include <stdio.h>

int sum(int num);

int main()
{
int num, lastEven, lastOdd;

printf("Enter the upper limit to find sum: ");
scanf("%d", &num);

lastOdd = (num & 1) ? num : num-1;

printf("Sum of all odd numbers from 1 to %d = %d ", num, sum(lastOdd));

return 0;
}

int sum(int num)
{

if(num <= 0)
return 0;

  
return (num + sum(num-2));
}

/*i tried until this */

there is no recursive allgorithm

general case question:yes

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