1.Basics of C++
From:
http://www.cplusplus.com/doc/tutorial/
/*
C++ Language Tutorial
1.Basics of C++
2.Control Structures
3.Compound data types
4.Object Oriented Programming
5.Advanced concepts
6.C++ Standard Library
*/
Table of contents
/* Basics of C++ Structure of a program Variables and types Constants Operators Basic Input/Output Program structure Control Structures Functions Overloads and templates Name visibility Compound data types Arrays Character sequences Pointers Dynamic Memory Data structures Other data types Classes Classes (I) Classes (II) Special members Friendship and inheritance Polymorphism Other language features Type conversions Exceptions Preprocessor directives C++ Standard Library Input/Output with files */
1.Basics of C++
The codes:
// 1. Basics of C++ /*********************************** 1 Structure of a program */ // my first program in C++ #include <iostream> using namespace std; int main () { cout << "Hello World!"; return 0; } // my second program in C++ #include <iostream> using namespace std; int main () { cout << "Hello World! "; cout << "I'm a C++ program"; return 0; } /* my second program in C++ with more comments */ #include <iostream> using namespace std; int main () { cout << "Hello World! "; // prints Hello World! cout << "I'm a C++ program"; // prints I'm a C++ program return 0; } /*********************************** 2 Variables. Data Types. */ // operating with variables #include <iostream> using namespace std; int main () { // declaring variables: int a, b; int result; // process: a = 5; b = 2; a = a + 1; result = a - b; // print out the result: cout << result; // terminate the program: return 0; } // initialization of variables #include <iostream> using namespace std; int main () { int a=5; // initial value = 5 int b(2); // initial value = 2 int result; // initial value undetermined a = a + 3; result = a - b; cout << result; return 0; } // my first string #include <iostream> #include <string> using namespace std; int main () { string mystring = "This is a string"; cout << mystring; return 0; } // my first string #include <iostream> #include <string> using namespace std; int main () { string mystring; mystring = "This is the initial string content"; cout << mystring << endl; mystring = "This is a different string content"; cout << mystring << endl; return 0; } /********************************* 3 Constants */ // test escape codes #include <iostream> #include <string> using namespace std; int main () { string s; s="one\ntwo\nthree\n"; cout << s; s="string expressed in \ two lines"; cout << s << endl; s="string expressed in \ two lines"; //space... cout << s << endl; s="b,c want:\142\143"; //octal cout << s << endl; s="b,c want:\x62\x63"; //hexadecimal cout << s << endl; return 0; } // defined constants: calculate circumference #include <iostream> using namespace std; #define PI 3.14159 #define NEWLINE '\n' int main () { double r=5.0; // radius double circle; circle = 2 * PI * r; cout << circle; cout << NEWLINE; return 0; } // test constants #include <iostream> using namespace std; #define PI 3.14 const n=10; int main () { PI=3.14159; //error n=100; //error return 0; } /****************************************** 4 Operators */ // assignment operator #include <iostream> using namespace std; int main () { int a, b; // a:?, b:? a = 10; // a:10, b:? b = 4; // a:10, b:4 a = b; // a:4, b:4 b = 7; // a:4, b:7 cout << "a:"; cout << a; cout << " b:"; cout << b; return 0; } // test rvalue #include <iostream> using namespace std; int main () { int a, b; a=2+(b=5); cout<<a<<" "<<b<<endl; a=b=a; cout<<a<<" "<<b<<endl; return 0; } // compound assignment operators #include <iostream> using namespace std; int main () { int a, b=3; a = b; a+=2; // equivalent to a=a+2 cout << a; return 0; } // more... #include <iostream> using namespace std; int main () { int a, b=3; a = b; a+=2; //5 cout << a << endl; a-=2; //3 cout << a << endl; a*=2; //6 cout << a << endl; a/=3; //2; cout << a << endl; a%=b; // 2 mod 3=2 cout << a << endl; a>>=1; // shift right 1, 10->1 cout << a << endl; a<<=3; // shift left 3, 1->1000 cout << a << endl; a&=15; // 1000 and 1111 -> 1000 cout << a << endl; a^=15; // 1000 xor 1111 -> 0111 cout << a << endl; a|=15; // 0111 or 1111 -> 1111 cout << a << endl; return 0; } // difference of: ++a a++ #include <iostream> using namespace std; int main () { int a, b=3; a=++b; // increased befor... cout << a << endl; b=3; a=b++; // include after... cout << a << endl; return 0; } // conditional operator #include <iostream> using namespace std; int main () { int a,b,c; a=2; b=7; c = (a>b) ? a : b; cout << c; return 0; } // comma operator #include <iostream> using namespace std; int main () { int a,b,c; c = ( a=2, b=7, a>b?a:b ); // cout << c; return 0; } // type casting operator #include <iostream> using namespace std; int main () { int i; double f=3.14; i=(int)f; cout << i << endl; i=int(f); cout << i << endl; i=98; cout << char(i) << endl; // same as pascal return 0; } /************************************* 5 Basic Input/Output */ // cout #include <iostream> using namespace std; int main () { cout << "First sentence.\n"; cout << "Second sentence.\nThird sentence."; return 0; } // i/o example #include <iostream> using namespace std; int main () { int i; cout << "Please enter an integer value: "; cin >> i; cout << "The value you entered is " << i; cout << " and its double is " << i*2 << ".\n"; return 0; } // cin with strings #include <iostream> #include <string> using namespace std; int main () { string mystr; cout << "What's your name? "; getline (cin, mystr); cout << "Hello " << mystr << ".\n"; cout << "What is your favorite team? "; getline (cin, mystr); cout << "I like " << mystr << " too!\n"; return 0; } // stringstreams #include <iostream> #include <string> #include <sstream> using namespace std; int main () { string mystr; float price=0; int quantity=0; cout << "Enter price: "; getline (cin,mystr); stringstream(mystr) >> price; //convert strings to numerical values cout << "Enter quantity: "; getline (cin,mystr); stringstream(mystr) >> quantity; cout << "Total price: " << price*quantity << endl; return 0; } // more #include <iostream> #include <string> using namespace std; int main () { int i,j; char c; cin>>i>>j; cin>>c; cout<<i<<" "<<j<<endl; cout<<c<<endl; return 0; } // cin always uses blank space character?
