SUM Recursive function in C - c

Question

I'm trying to recursive function in C that calculates the sum of the numbers from x to max (inclusive). For example, sum (4, 7) would compute 4 + 5 + 6 + 7 and return the value 22. The function code a must be recursive so you are not allowed to use any conventional loop constructs.
I have this and i think it should work but i'm not entirely sure why its not
#include <stdio.h>
int main()
{
int sum (x, max);
int total, y, x, max;
if (x<max){
y=x+1;
total = x+sum(y,max);
return total;
return x;
}
return 0;
}
Thanks for any help with this in advance!

Answer 1

Here is one possible solution:
#include <stdio.h>
int sum_in_range(int a, int b){
if(a != b){
return sum_in_range(a+1,b)+a;
}
else{
return b;
}
}
int main(void) {
// your code goes here
printf("%d",sum_in_range(2,4));
return 0;
}

Answer 2

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int sum(int s,int max)
{
if(s==max)
{
return s;
}
else
{
return(s+sum(s+1,max));
}
}
int main()
{
int r,s,max;
printf("\n enter s and max");
scanf("%d%d",&s,&max);
r=sum(s,max);
printf("%d",r);
}

Answer 3

I spotted some errors on your code. I'm not a pro yet but here's what I think
I just edit your code. removed, added and rearranged some stuff*/
/*First, let's look at your code*/
#include <stdio.h>
#include <stdlib.h>
int main()
{
int sum(x, max);//I think what you want to do here is declare a function but instead declaring, you define it here because you added semicolon (;)
int total, x, y, max;
if(x < max)
{
y = x + 1;
total = x + sum(y, max); //you don't have a function declaration for "sum"
return total;
return x; //this will never return since you already "return the total before this"
}
return 0;
}
//////////////////////////////////////////////////////////////
/*And I think this is what you want to do*/
#include <stdio.h>
#include <stdlib.h>
int main()
{
int x = 4, max = 6; //We declare this here for the "sum" function. This way "sum" function can recognize these variables
int total = x; //be sure to set the total to x.
//you can make a void function for this instead of "int". but either way, it can do the job.
void sum(int y) //no need to pass a "max" because "max" is already recognized by the "sum" function since we declare the variables at the top of "main" function
{
if(x < max)//don't make it x <= max. Because of the argument "total = total + (x + 1)" on this function. If you do, the total will exceed.
{
//You can see here why we set the value of "total" to x.
total = total + (x + 1);//And also, you can see why we didn't make the argument in if() statement like this: if(x <= max).
x++;//increment "x" every loop
//call the function again and pass the total until x == max.
sum(total);
}
}
//pass the x
sum(x);
//check the answer
printf("The total is %d\n\n", total);
return 0;
}
//////////////////////////////////////////////////////////////
/*It looks messy with comments*/
/*Here's the code looks like without a comment.It's pretty short code if you look remove the comments.. LOL..*/
#include <stdio.h>
#include <stdlib.h>
int main()
{
int x = 4, max = 6;
int total = x;
void sum(int y)
{
if(x < max)
{
total = total + (x + 1);
x++;
sum(total);
}
}
sum(x);
//check the answer
printf("The total is %d\n\n", total);
return 0;
}