My C program is recursing infinitely and I cannot figure out why - c

Question

This program is supposed to take a name from a user and output it backwards. Our professor said we had to use recursion and I am struggling with getting to not recurse infinitely. Please help.
#include <stdio.h>
#include <string.h>
void reversedWord(char input[],int size)
{ int count;
int count2;
if(count==0) {
count2=size;
}
count2=count2-1;
char store;
store=input[count2];
input[count2]=input[count];
input[count]=store;
count=count+1;
if(count>size)
{
return;
}
return reversedWord(input,size);
}
int main()
{
char input[100];
printf("Please enter your name: ");
scanf("%s",input);
int size=strlen(input);
reversedWord(input,size);
printf("\n Your name backwards: %s \n",input);
}

Answer 1

First in the above code, you need to initialize your variables count and count2.
The statements int count; means that you are declaring the variable count of integer type. But it doesn't hold any value.
for this example to have the recursion working, you need to pass 3 parameters(input string, start_index,end_index) at each call to the function.
Here's the modified code to have this working
void reversedWord(char input[],int start,int end)
{
end=end-1;
char store;
store=input[end];
input[end]=input[start];
input[start]=store;
start=start+1;
if(start>=end)
{
return;
}
return reversedWord(input,start,end);
}
int main()
{
char input[100];
printf("Please enter your name: ");
scanf("%s",input);
int size=strlen(input);
reversedWord(input,0,size);
printf("\n Your name backwards: %s \n",input);
}

Answer 2

Since you use counters inside your recursive function they should be static, I suggest reading documentation about what static does in the C language if it is new to you.
Below is your code with working recursion, but your algorithm for word reversion contains an error. I believe you can solve it yourself with a bit of thought, so I will just give a hint - it reverses the word, but then reverses it back right again.
#include<stdio.h>
#include<string.h>
void reversedWord(char input[],int size)
{
static int count = 0;
static int count2;
if(count==0) {
count2=size;
}
count2=count2-1;
char store;
store=input[count2];
input[count2]=input[count];
input[count]=store;
count=count+1;
if(count>size)
{
return;
}
reversedWord(input,size);
return;
}
int main()
{
char input[100];
printf("Please enter your name: ");
scanf("%s",input);
int size=strlen(input);
reversedWord(input,size);
printf("\n Your name backwards: %s \n",input);
}

Answer 3

I think even if you assign zero to count and count2 ,this will not work because you are calling the function recursively.
So every time you call reversedWord(input,size) the values are again initialized;
> void reversedWord(char input[],int size) { int count; //initialized
> for every recursive call
> int count2; //initialized for every recursive call
> if(count==0) {
> count2=size;
> }
> count2=count2-1;
> char store;
> store=input[count2];
> input[count2]=input[count];
> input[count]=store;
> count=count+1;
> if(count>size)
> {
> return;
> }
> return reversedWord(input,size); }
A better solution would be to declare these two variables count and count2 as static.
static int count,count2 ;
by default the static variable are assigned as 0 and they share a common memory,so no new space is assigned to them and the new values get reflected on the same variable(initialized just once)