C++ Tutorial/string/string concatenation

Материал из C\C++ эксперт
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Concatenate two strings

#include <iostream>
#include <string>
using namespace std;
int main()
{
  string str1("A");
  string str2("B");
  string str3("G");
  string str4;
  cout << "  str1: " << str1 << endl;
  cout << "  str2: " << str2 << endl;
  cout << "  str3: " << str3 << "\n\n";
  // Concatenate two strings.
  str4 = str1 + str3;
  cout << "str4 after begin assigned st1+str3: " << str4 << "\n\n";
  return 0;
}

overloaded string concatenation operator

#include <iostream>
using std::cout;
using std::endl;
#include <string>
using std::string;
int main()
{
   string s1( "AA" );
   string s2( " AAB" );
   string s3;
   // 
   cout << "\n\ns1 += s2 yields s1 = ";
   s1 += s2; // test overloaded concatenation
   cout << s1;
   return 0;
}
s1 += s2 yields s1 = AA AAB"

overloaded string concatenation operator with C-style string

#include <iostream>
using std::cout;
using std::endl;
#include <string>
using std::string;
int main()
{
   string s1( "AA" );
   string s2( " AAB" );
   string s3;
   // 
   cout << "\n\ns1 += \" to you\" yields" << endl;
   s1 += " to you";  
   cout << "s1 = " << s1 << "\n\n";
   return 0;
}
s1 += " to you" yields
s1 = AA to you

Plus string together

#include <iostream>
#include <string>
using namespace std;
int main()
{
  string sentence, words[10];
  int pos = 0, old_pos = 0, nwords, i = 0;
  sentence = "Eskimos have 23 ways to ";
    sentence += "describe snow";
  while (pos < sentence.size()) {
    pos = sentence.find(" ", old_pos);
    words[i++].assign(sentence, old_pos, pos - old_pos);
    cout << words[i - 1] << endl; //print words
    old_pos = pos + 1;
  }
  nwords = i;
  sentence = "C++ programmers ";
  for (i = 1; i < nwords -1; ++i)
    sentence += words[i] + " ";
  sentence += "windows";
  cout << sentence << endl;
}