Im in c and im trying to work a homework problem but the out

Im in c++ and im trying to work a homework problem but the output is not the right answer and I dont know what Im doing wrong in my code. Bellow is my code name int replace(char * str, char ch1, char ch2). However the int main(){} was provided by the professor. Our homework is based on pointers and strings. This is the question:

Write the function replace(). The function has three parameters: a char * s, a char c1 and a char c2. Replace all instances of c1 with c2. Return a pointer to the first character in s.

#include <string>

#include <iostream>

#include <cassert>

using namespace std;

int replace(char * str, char ch1, char ch2)

{

int changes=0;

while(*str!=\'\\0\')

{

if(*str==ch1)

{

*str=ch2;

changes++;

}

str++;

}

return changes;

}

int main()

{

cout << \"\ replace(dog, \'o\', \'i\') expects \\\"Labradiidle\\\"\" << endl;

cout << \" -- \\\"\" << replace(dog, \'o\', \'i\') << \"\\\"\" << endl;

}

Solution

char& replace(char * str, char ch1, char ch2)

{

char *ref;

ref=str;//assign ref the pointer to first character

while(*str!=\'\\0\')

{

if(*str==ch1)

{

*str=ch2

}

str++;

}

return ref;

}

//dont count no of changes instead assign address of //first character to another char pointer