visual c++ - "function already has a body" - visual-c++

Question

Here is my declaration in question, I even use include guards:
Edit: I'm including the entire header if this will help answer any additional
questions one might have.
#ifndef STRING_H
#define STRING_H
#include<iostream>
class String
{
public:
String(const char * s = "");
String(const String & s);
String operator = (const String & s);
char & operator [] (int index);
int size();
String reverse();
int indexOf(char c);
int indexOf(String pattern);
bool operator == (String s);
bool operator != (String s);
bool operator > (String s);
bool operator < (String s);
bool operator >= (String s);
bool operator <= (String s);
String operator + (String s);
String operator += (String s);
void print(std::ostream & out);
void read(std::istream & in);
static int strLen(const String &s);
static String strCpy(const String &s, int length);
static String strDup(const String &s);
static bool strCmp(const String &s, const String &t);
~String();
private:
bool inBounds(int i)
{
return i >= 0 && i < len;
}
char * buf;
int len;
};
#endif
And here is my definition:(starting form line 183)
String String::operator = (const String & s)
{
String t(s);
return t;
}
And I keep getting this error:
>c:\users\omive_000\documents\visual studio 2013\projects\string\string\string.h(183): error C2084: function 'String String::operator =(const String &)' already has a body
1> c:\users\omive_000\documents\visual studio 2013\projects\string\string\string.h(11) : see previous definition of '='
can anyone offer me an explanation as to why this error occurs?

Answer 1

Definitions normally don't belong into header files.
You can declare and define your function inline, inside your include guards
You can use a cpp file
That said, your code looks fishy. It does not do what it seems to do. There is no assignment to this or it's variables happening. But that's a bug and not a compiler error.