Please tell me the error in this code.

Question

#include<stdio.h>
char* reverse(char*);
int main()
{
printf("%s",reverse("Computer"));
return 0;
}
char* reverse(char *p)
{
int l,i;
char ch;
for(l=0; *(p+l)!='\0'; l++);
for(i=0; i<l/2; i++)
{
ch=*(p+i);
*(p+i)=*(p+l-1-i);
*(p+l-1-i)=ch;
}
return(p);
}

Question:I made this program to reverse the string using pointer but it shows an error can anyone tell me the error in this code please.

Answer 1

#include<stdio.h>
void reverse(char*); // void return type is enough because we are passing the pointer so changes automatically happen
int main()
{
char st[] = "Computer";
reverse(st);
printf("%s",st);
return 0;
}
/*
+---+---+---+---+---+---+---+---+
| C | o | m | p | u | t | e | r |
+---+---+---+---+---+---+---+---+
| |
a points to 0 b points to length-1
a++ from C -> o -> m -> p
b-- frim r -> e -> t -> u
On the process the value of "a" and "b" get swap.*/
void reverse(char *p)
{
int l,i;
char ch;
char *a, *b;
a = p; // pointing to the string
b = p; // pointing to the string

for(l=0; *(p+l)!='\0'; l++);
b = (p+l-1); // pointing to the last element of the string
for(i=0; i<l/2; i++)
{
ch=*b;
*b=*a;
*a=ch;

a = (p+(i+1)); // or a++;
b = (p+l-1-(i+1)); // or b--;
}

}

Answer 2

Haven't tested the code yet, but just looking through it there is a semicolon directly after the closing parenthesis of the first for loop. This means that that for loop has no body.
for(l=0; *(p+1)!='\0'; l++); <--- remove semicolon