i will provide error.

declare template function as,
T Add(T a, T b){return a+b ;}

There are two things to be considered here.

First, T will be an unknown type in the place where we call 
which gives a compilation error.

Second, if we call like this:

std::string c = Add("SAM", "SUNG"); or,
char* c = Add("SAM", "SUNG"); 

the compiler will convey an error since the arguments to 
Add are interpretted as char pointers. The error may be 
something like, "cannot add two pointers....".

The error is adding Two pointers isn't alowed in C/C++.
The compiler imlicitly treats "SAM" as const char*. We need 
to write a function with "explicit" keyword declaration like

explicit  char * Add (const char* x1, const char* x2) 
{
  // check for null pointers.
  // allocate strlen(x1)+strlen(x2)+1 using malloc 
  // say    char*a1 = malloc...;
  // check if malloc returns null..take corrective actions

  // strcpy (a1, x1);
  // strcat (a1, x2);
  //strcat (a1, '\0');

  return a1; // ask the caller to free the memory allocated
  //  for a1

}

since this function is writen explicit the compiler will 
invoke this function and not call the default template 
function.
this is what appears to me. haven't coded and verified.

// Regards, SADIQ

1) Compiler will throw the error as C++ doesnt support + 
operator for string. Another point is T c = Add
("SAM","SUNG"), where the function call assign to a 
TEMPLATE object type, it syntactical error.

2)We need to write a seperate add function as given below

char* Add( const char *s1, const char*s2);

This will solve the problem