// Rick Mercer 5-Oct-1995
// Demonstrate substrings and concatenation
//
#include <cstring.h>   // Borland's 4.5 cstring works (except for empty)
#include <iostream.h>
#include <assert.h>

void main()
{
   string s1, s2 ;

   s1 = "abcDEFghiHKLabcDEF" ;

   // Beginning at s1[8], create and display a 5 character substring
   cout << "s1.substr(8, 5) == " << s1.substr(8, 5) << endl ;
   assert(s1.substr(8, 5) == "iHKLa") ;

   // Change s1 and s2 for use in the next several examples
   s1 = "A new" ;
   s2 = " string" ;

   // A string object, string literal, or char can be concatenated with +=
   s1 += s2 ;
   // assert: s1's characters are "A new string"

   s1 += "--append me" ;
   // assert: s1's characters are "A new string--append me"

   s1 += '!' ;
   // assert: s1's characters are "A new string--append me!"

   cout << "\ns1: " << s1 << endl << endl ;
   // assert: 's1: A new string--append me!' is displayed

   // The following free functions are part of the string module:

   //-----relational operators

   // When comparing strings, remember that 'A' is considered less than 'B',
   // 'z' is greater than 'y'. Therefore "Able" is less than "Baker".  
   // Think alphabeltically.  
   s1 = "Able" ;
   s2 = "Baker" ;

   if(s1 <  s2)     cout << "True" ;
   if(s1 >  s2)     cout << "False" ;
   if(s1 <= s2)     cout << "True" ;
   if(s1 >= s2)     cout << "False" ;
   if(s1 == "Able") cout << "Yes" ;
   if(s1 != "Able") cout << "No" ;
   cout << endl ;
   // assert: 'TrueTrueYes' is output

   //-----The + concatenation operator
   s1 = "abc" ;
   s2 = "123" ;
   s1 = s1 + s2 ;
   // assert: s1 == "abc123"

   s1 = s1 + "xyz" ;
   // assert: s1 == "abc123xyz"

   s1 = "000" + s1 ;
   // assert: s1 == "000abc123xyz"

   s1 = '!' + s1 + '!' ;
   // assert: s1 == "!000abc123xyz!"

   cout << "\nAfter 4 concatenations, s1 == " << s1 << endl ;
   // assert: s1 == 'After 4 concatenations, s1 == !000abc123xyz!'
}