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diff --git a/c++.html.markdown b/c++.html.markdown new file mode 100644 index 00000000..8cf72e47 --- /dev/null +++ b/c++.html.markdown @@ -0,0 +1,349 @@ +--- +language: c++ +filename: learncpp.cpp +contributors: + - ["Steven Basart", "http://github.com/xksteven"] +lang: en +--- + +I am writing this to highlight the differences and +additions that C++ has with respect to C. My +suggestion would be to follow the C tutorial first +then look here for the additions and differences. + +```c++ +/////////////////////////////////////// +// C++ differences +/////////////////////////////////////// + + +//In C++ +//cannot use void main() +int main() { //or int main(int argc, char **argv) + //cannot end with return; + return 0; + //Can also end without return statement +} + +//In C++ +/* + //This could lead to compiler errors and is discouraged + //#if 0 #endif pairs are encouraged instead +*/ + +//In C++ +sizeof(10) //Typically 4 +sizeof('c') == 1 + +//In C +sizeof('c') == sizeof(10) //true chars are passed as ints + + +//In C++ strict prototyping +void func(); //function which accepts no arguments + +//In C +void func(); //function which may accept arguments + + +//In C++ +for(int i = 0; i < 10; i++) {;} +//In C must int i must be declared before + + +//C++ Supports Function overloading +//Provided each function takes different +//parameters + +void printing(char const *myString) +{printf("String %s\n",myString);} //Hello + +void printing(int myInt) +{printf("My int is %d",myInt);} //15 + +int main () +{ + printing("Hello"); + printing(15); +} + + + +//C++ Default Function Arguments +void two_ints(int a = 1, int b = 4); + +int main() +{ + two_ints(); // arguments: 1, 4 + two_ints(20); // arguments: 20, 4 + two_ints(20, 5); // arguments: 20, 5 +} + + +//C++ added the nullptr which is different from 0 +int *ip = nullptr; // OK +int value = nullptr; // error: value is no pointer + + +/////////////////////////////////////// +// C++ Additions ontop of C +/////////////////////////////////////// + + +/////////////////////////////////////// +// C++ Namespace +/////////////////////////////////////// + +//Namespaces allow you to define your own +//functions and variables for use + +// Use '::' to change variable (or function) scope +// Putting '::' before a function or variable will +// reference a global scope + +// This allows you to make normal c library calls +// std is for standard library +using namespace std; + +#include <stdio.h> + +int counter = 50; // global variable + +int main() +{ + for (int counter = 1; // this refers to the + counter < 2; // local variable + counter++) + { + printf("Global var %d local var %d\n", + ::counter, // global variable + counter); // local variable + // => Global var 50 local var 1 + } +} + +// Namespaces can be nested + + +namespace myFirstNameSpace +{ + namespace myInnerSoul + { + cos(int x) + { + printf("My inner soul was made to program."); + } + } +} + +namespace anotherNameSpace +{ + cos(int x) {;} //does nothing +} + +int main() +{ + //Specify the full path because main is outside of both namespaces. + //Will print out My inner soul was made to program. + myFirstNameSpace::myInnerSoul::cos(60); +} + + +/////////////////////////////////////// +// C++ Strings +/////////////////////////////////////// + +//Strings in C++ are Objects and have many functions +myString = "Hello"; +myOtherString = " World"; + +myString + myOtherString; // => "Hello World" + +myString + ' You'; // => "Hello You" + +myString != myOtherString; //True + +//An example of a string method +myString.append(" Dog"); // => "Hello Dog" + + +/////////////////////////////////////// +// C++ Input Output +/////////////////////////////////////// + +//C++ input and output streams +//cin, cout, cerr, << is insertion and >> is extraction operator +#include <iostream> + +using namespace std; + +int main() +{ + + int myInt; + + //Prints to stdout (or terminal/screen) + cout << "Enter your fav number:\n" + //Takes in input + cin >> myInt; + + //cout can also be formatted + cout << "Your fav number is " << myInt << "\n" + //Your fav number is ## + + cerr << "Used for error messages" +} + + +/////////////////////////////////////// +// C++ Classes +/////////////////////////////////////// + + +//First example of classes +#include <iostream> + +//define a class +class Doggie +{ + std::string name; + int weight; + + // These are only the declarations + //Can also have private and protected + public: + //The public methods (can also include variables) + + // Default constructor + Doggie(); + + void setName(std::string dogsName); + void setWeight(int dogsWeight); + void printDog(); + + //Can define functions within class declaration too + void dogBark() {std::cout << "Bark Bark\n"} + + //Destructors are methods that free the allocated space + ~doggieDestructor(); + //if no destructor compiler defines the trivial destructor + +//Classes are similar to structs and must close the } with ; +}; + +// This is the implementation of the class methods +// Also called the definition +void Doggie::Doggie () { + std::cout << "A doggie is born. Woof!\n"; +} + +void Doggie::setName (std::string doggie_name) { + name = doggie_name; +} + +void Doggie::setWeight (int doggie_weight) { + weight = doggie_weight; +} + +void Doggie::printDog () { + std::cout << "Dog is " << name << " weighs" << weight << "\n"; +} + +void Doggie::~doggieDestructor () { + delete[] name; + delete weight; +} + +int main () { + Doggie deedee; // prints out a doggie is born. Woof! + deedee.setName ("Barkley"); + deedee.setWeight(1000000); + deedee.printDog; + //prints => Dog is Barkley weighs 1000000 + return 0; +} + + +//C++ Class inheritance + +class German_Sheperd +{ + //This class now inherits everything public and protected from Doggie class + Doggie d_dog; + + //Good practice to put d_ in front of datatypes in classes + std::string d_type; + + public: + void dogType() {d_type = "German Sheperd";} +}; + + + +/////////////////////////////////////// +// C++ Exception Handling +/////////////////////////////////////// + +try { + throw 12.25; // throws a double no handler declared +} catch (int errorNum) +{ + std::cout << "I caught an int " << errorNum << "\n"; +//default catcher +} catch (...) +{ + std::cout << "I got an error. Not sure what but I can pass it up."; + throw; +} + + +/////////////////////////////////////// +// C++ Operator Overloading +/////////////////////////////////////// + +// In C++ you can overload operators such as +, -, new, etc. + +#include <iostream> +using namespace std; + +class Vector { + public: + double x,y; + Vector () {}; + Vector (double a, double b) : x(a), y(b) {} + Vector operator + (const CVector&); + Vector operator += (const CVector&); +}; + +Vector Vector::operator+ (const Vector& rhs) +{ + Vector temp; + temp.x = x + rhs.x; + temp.y = y + rhs.y; + return temp; +} + +Vector Vector::operator+= (const Vector& rhs) +{ + x += rhs.x; + y += rhs.y; + return *this; +} + +int main () { + Vector up (0,1); + Vector right (1,0); + Vector result; + // This calls the Vector + operator + // Vector up calls the + (function) with right as its paramater + result = up + right; + // prints out => Result is upright (1,1) + cout << "Result is upright (" << result.x << ',' << result.y << ")\n"; + return 0; +} + +``` +Futher Reading + +for more resources see: http://www.icce.rug.nl/documents/cplusplus/ +for other reference material: http://www.cplusplus.com/doc/tutorial/ |