Basic String Operations

• Assignment Operation (=)

  string str1 = "Welcome";

  string str2;

  str2 = str1; // assign the string literal of str1 to str2

  str1 = string("Jones"); //or str1 = "Jones“;
• Assignment Operation (=)

  string str1 = "Welcome";

  string str2;

  str2 = str1; // assign the string literal of str1 to str2

  str1 = string("Jones"); //or str1 = "Jones“;
• Assignment Operation using assign() method

  string str1 = "Welcome";

  string str2 = “Hello";

  str1.assign(str2); // assign the string literal of str2 to str1

  cout << str1; //display Hello
• Assignment Operation using assign() method

  string str1 = "Welcome";

  string str2 = “Hello";

  str1.assign(str2); // assign the string literal of str2 to str1

  cout << str1; //display Hello
• Concatenation Operation (+)

  string str1 = "Welcome";

  string str2 = "to C++ Programming!";

  string str3 = str1 + " " + str2; //the value of str3 is Welcome to C++ Programming!

  str1 += str2; //str1 is WelcometoC++Programming!

  str3 = "Welcome" + "to C++ Programming!"; //illegal statement concatenation works if there is at least 1 string data type like str3 = str1 + "Mickey";
• Concatenation Operation (+)

  string str1 = "Welcome";

  string str2 = "to C++ Programming!";

  string str3 = str1 + " " + str2; //the value of str3 is Welcome to C++ Programming!

  str1 += str2; //str1 is WelcometoC++Programming!

  str3 = "Welcome" + "to C++ Programming!"; //illegal statement concatenation works if there is at least 1 string data type like str3 = str1 + "Mickey";
• Concatenation Operation (+)

  string x = "10";

  string y = "20";

  string z = x + y;

  cout << z << endl; //the output is 1020
• Concatenation Operation (+)

  string x = "10";

  string y = "20";

  string z = x + y;

  cout << z << endl; //the output is 1020
• Convert string to integer (stoi)

  string x = "10";

  string y = "20";

  int z = stoi(x) + stoi(y);

  cout << z << endl; //the output is 30
• Convert string to integer (stoi)

  string x = "10";

  string y = "20";

  int z = stoi(x) + stoi(y);

  cout << z << endl; //the output is 30
• Other conversion for numeric values:

  stol() string to long

  stoll() string to long long

  stof() string to float

  stod() string to double

  stold() string to long double
• String Length/Size Method/Function

  string str1 = "Welcome";

  string str2 = "to C++ Programming!";

  int len = str1.length(); //or str1.size(); // len is 7

  int stringLen = str1.size() + str2.length(); //stringLen is 26
• String Length/Size Method/Function

  string str1 = "Welcome";

  string str2 = "to C++ Programming!";

  int len = str1.length(); //or str1.size(); // len is 7

  int stringLen = str1.size() + str2.length(); //stringLen is 26
• Access String Characters

  string str1 = "Welcome";

  string str2 = "to C++ Programming!";

  cout << str1[0]; //display W

  cout << str1[3]; //display c

  cout << str1[str1.length() - 1]; //display e or last character of the string literal

  str2[0] = ‘J’; //str2 is Jo C++ Programming!
• Access String Characters

  string str1 = "Welcome";

  string str2 = "to C++ Programming!";

  cout << str1[0]; //display W

  cout << str1[3]; //display c

  cout << str1[str1.length() - 1]; //display e or last character of the string literal

  str2[0] = ‘J’; //str2 is Jo C++ Programming!
• Access String Characters using at() method

  string str1 = "Welcome";

  string str2 = "to C++ Programming!";

  cout << str1.at(0); //display W

  cout << str1.at(3); //display c

  cout << str1.at(str1.size() – 1); //display e or the last character of the string literal

  str2.at(0) = ‘J’; //str2 is Jo C++ Programming!
• Access String Characters using at() method

  string str1 = "Welcome";

  string str2 = "to C++ Programming!";

  cout << str1.at(0); //display W

  cout << str1.at(3); //display c

  cout << str1.at(str1.size() – 1); //display e or the last character of the string literal

  str2.at(0) = ‘J’; //str2 is Jo C++ Programming!