An introduction to the C++ programming language for game engine development.

2. ‫معرفی‬String
‫معرفی‬I/O Stream‫ها‬

3. 01. string compose(const string& name, const string& domain)
02. {
03. return name + '@' + domain;
04. }
05.
06. auto addr = compose("dmr","bell–labs.com");
01. void m2(string& s1, string& s2)
02. {
03. s1 = s1 + 'n'; // append newline
04. s2 += 'n'; // append newline
05. }

4. 01. string name = "Niels Stroustrup";
02.
03. void m3()
04. {
05. string s = name.substr(6,10); // s = "Stroustrup"
06. // name becomes "nicholas Stroustrup"
07. name.replace(0,5,"nicholas");
08. // name becomes "Nicholas Stroustrup"
09. name[0] = toupper(name[0]);
10. }

5. 01. string incantation;
02.
03. void respond(const string& answer)
04. {
05. if (answer == incantation) {
06. // perform magic
07. }
08. else if (answer == "yes") {
09. // ...
10. }
11. // ...
12. }

6. 01. void f()
02. {
03. cout << 10;
04. }
01. void g()
02. {
03. int i {10};
04. cout << i;
05. }

7. 01. void h(int i)
02. {
03. cout << "the value of i is ";
04. cout << i;
05. cout << 'n';
06. }
the value of i is 10
01. void h2(int i)
02. {
03. cout << "the value of i is " << i << 'n';
04. }

8. 01. void f()
02. {
03. int i;
04. cin >> i; // read an integer into i
05. double d;
06. // read a double-precision floating-point number into d
07. cin >> d;
08. }
01. void hello()
02. {
03. cout << "Please enter your namen";
04. string str;
05. cin >> str;
06. cout << "Hello, " << str << "!n";
07. }

9. 01. void hello_line()
02. {
03. cout << "Please enter your namen";
04. string str;
05. getline(cin,str);
06. cout << "Hello, " << str << "!n";
07. }

10. 01. struct Entry {
02. string name;
03. int number;
04. };
01. ostream& operator<<(ostream& os, const Entry& e)
02. {
03. return os << "{"" << e.name << "", " << e.number << "}";
04. }

11. 01. // read { "name" , number } pair. Note: formatted with { " " , and }
02. istream& operator>>(istream& is, Entry& e)
03. {
04. char c, c2;
05. if (is>>c && c=='{' && is>>c2 && c2=="") { // start with a { "
06. // the default value of a string is the empty string: ""
07. string name;
08. while (is.get(c) && c!='"') // anything before a " is part of the name
09. name+=c;
10. if (is>>c && c==',') {
11. int number = 0;
12. if (is>>number>>c && c=='}') { // read the number and a }
13. e = {name,number}; // assign to the entry
14. return is;
15. }
16. }
17. }
18. is.setf(ios_base::failbit); // register the failure in the stream
19. return is;
20. }

12. { "John Marwood Cleese" , 123456 }
{"Michael Edward Palin",987654}
01. for (Entry ee; cin>>ee; ) // read from cin into ee
02. cout << ee << 'n'; // write ee to cout
{"John Marwood Cleese", 123456}
{"Michael Edward Palin", 987654}