// Illustrates use of of various C++ string functions.

#include <iostream>
#include <string>
#include <cstdlib>

using std::string;
using std::cout; using std::endl;

int main(){
  // CONSTRUCTION:
  string s0,         // the empty string
         s1 = "A string",
         s2("Another string"), 
         s3(s1),     // copy constructor
         s4(s1,2,6); // copy constructor, selected part
                     // 6 characters from s: "string"

  cout << s4 << endl; // "string"
  
  // ELEMENT ACCESS:
  cout << "s1[0] = " << s1[0] << endl;        // A
  cout << "s1[10] = " << s1[10] << endl;      // Index out of range. Risky at run time!

  cout << "s1[0] = " << s1.at(0) << endl;     // A
//cout << "s1[10] = " << s1.at(10) << endl;   // Compiles. Run time error : out of range.

  // ASSIGNMENT:
  s0 = s2;                                    // Assignment - copies all chars in s2.
  cout << s0 << endl;                         // "another string"

  // CONVERSION TO C-STYLE STRINGS:
  s1 = "1234";
  const char *str1 = s1.c_str();              // C++ string   ->  C string
  int str1_int = std::atoi(str1);             // C-style function: atoi applied
//int s1_int = std::atoi(s1);                 // Not possible to call atoi on a C++ string:
                                              // Cannot convert string to const char* 
  cout << "char*: " << str1                   // char*: 1234
       << " int: "  << str1_int << endl;      // int: 1234

  // COMPARISON:
  cout << "compare abc and def: "
       << string("abc").compare("def")        // -1
       << endl; 

  bool b = string("abc") < string("def");     // Comparison with the operator < is 
  cout << "b: " << b << endl;                 // also possible!    b: 1
 
  s1 = s2;
  cout << "compare s1 and s2: "               // s2 has just been copied to s1 - thus equal.
       << s1.compare(s2) << endl;             // 0

  // INSERT AND APPEND:
  string s5 = "Poul", s6 = "Hansen";
  s5 += ' ';
  s5 += s6;
  cout << "Appended names: " << s5 << endl;   // Poul Hansen

  s5.insert(5, "Ib ");                        // Insert "Ib" as middle name.
  cout << "Insert Ib middle name: " << s5     // Poul Ib Hansen
       << endl;

  s5 = "Peter", s6 = "Andersen";
  cout << s5 + " " + s6 << endl;              // Concatenation: 
                                              // Peter Andersen
}