strplus.cpp

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// strplus.cpp
// overloaded '+' operator concatenates strings
#include <iostream>
using namespace std;
#include <string.h>      //for strcpy(), strcat()
#include <stdlib.h>      //for exit()  
////////////////////////////////////////////////////////////////
class String             //user-defined string type
   {
   private:
      enum { SZ=80 };                //size of String objects
      char str[SZ];                  //holds a string
   public:
      String()                       //constructor, no args
         { strcpy(str, ""); }
      String( char s[] )             //constructor, one arg
         { strcpy(str, s); }
      void display() const           //display the String
         { cout << str; }
      String operator + (String ss) const  //add Strings
         {
         String temp;                //make a temporary String
         if( strlen(str) + strlen(ss.str) < SZ )
            {
            strcpy(temp.str, str);   //copy this string to temp
            strcat(temp.str, ss.str);  //add the argument string
            }
         else
            { cout << "\nString overflow"; exit(1); }
         return temp;                //return temp String
         }
   };
////////////////////////////////////////////////////////////////
int main()
   {
   String s1 = "\nMerry Christmas!  ";   //uses constructor 2
   String s2 = "Happy new year!";        //uses constructor 2
   String s3;                            //uses constructor 1

   s1.display();                         //display strings
   s2.display();
   s3.display();

   s3 = s1 + s2;                         //add s2 to s1,
                                         //   assign to s3
   s3.display();                         //display s3
   cout << endl;
   return 0;
   }