class string {
  public:
    string( char const* t ) : s(t) {}
   ~string() { delete s; }
    char const* c_str() const { return s; }
  private:
    char const* s;
  };

there is a problem in the above code
can anyone help

char const* should be const char*. May I ask why do you want to hold a constant string?

maybe he needs a const char* just to print it out. what else ?.... can we both agree that he should get back to basic oop and data types classroom again. just my opinion.

Just an observation...you do realize that a very useful and well defined string class already exists and you can include it in your program with #include <string> (if you want to use a string class...).