From C to C Why C is much

From C to C++

Why C++ is much more fun than C (C++ FAQ)? 1. Classes & methods - OO design 2. Generic programming - Templates allow for code reuse 3. Stricter type system (e. g. function args) 4. Some run-time checks & memory control A common and mature language that gives you high level and low level control Have fun 2

Why C++ is much more fun than c (C+ FQA)? 1. 2. 3. 4. 5. Tons of corner cases Duplicate features Cryptic syntax Undecidable syntax (uncompilable progarms!) No two compilers agree on it Probably one of the hardest computer languages to master. Have fun 3

History auto, lambdas, threading, … Auto return type, generic lambdas, binary literals, … C++03 C++11 C++14 Minor changes Major changes Default in g++ The C++ Prog. Manual (8590) 4 C++98 Minor changes

History auto, lambdas, threading, … Auto return type, generic lambdas, binary literals, … C++03 C++11 C++14 Minor changes Major changes Default in g++ The C++ Prog. Manual (8590) C++98 Minor changes We’ll learn parts of C++-11, Mostly parts that makes C++ more “pythonic” while keeping it efficient 5

Future C++17 6 C++20 …

Course Objectives 1. Learn the language 2. Practice of programming � Design � Testing & Debugging � Efficiency & Portability � Modularity 7

Course structure Overloading Object Oriented programing • The C++ version. Copying and Conversion • A hidden monster Compile time polymorphism Other topics 8 • The basic mechanism underlying many of the extensions. • Templates - Generics++. • Statics, etc.

First Program in C++ // This line includes the standard // I/O library file (similar to “copy here this file”) #include <iostream> int main() { std: : cout << "Hello class!n"; return 0; } 9

Compiling & Running… In this course we’ll use ubuntu standalone or c 9 io (ubuntu on the cloud) with the gcc (gnu compiler collection): > g++ -Wall -Wvla -Werror -g -D_GLIBCXX_DEBUG -std=c++11 hello. cpp –o hello > hello Hello class! > 10

The missing types Fill in missing types from C, in somewhat crude way 11

strings in C++ 12 #include <iostream> More about string functions: #include <string> http: //www. cppreference. com/cppstring int main() { std: : string str; int a; double b; std: : cin >> str >> a >> b; if(std: : cin. fail()) { std: : cerr << "input problemn"; return 1; } std: : cout << "I got: "<< str << ' ' << a << ' ' << b << std: : endl; }

Boolean variables #include <iostream> int main() { int a = 5; bool is. Zero = (a == 0); // same conditions if(!is. Zero && is. Zero==false && is. Zero!=true && !!! is. Zero && a ) { std: : cout << "a is not zeron"; } } 13

Boolean variables #include <iostream> int main() Good { style int a = 5; bool is. Zero = (a == 0); // same conditions if(!is. Zero && is. Zero==false && is. Zero!=true && !!! is. Zero && a ) { std: : cout << "a is not zeron"; } } 14

Enum (C)

User Defined Type - enum Enumerated data - a set of named constants. Usage: enum [identifier]{enumerator list} enum Season { WINTER, SPRING, SUMMER, AUTUMN }; // = 0 by default // = WINTER + 1 // = WINTER + 2 // = WINTER + 3 enum {SUNDAY=1, MONDAY, TUESDAY, …}; // nameless enum Color {BLACK, RED, GREEN, YELLOW, BLUE, WHITE=7, GRAY}; // 0 1 2 3 4 7 8 16

enum Season { WINTER, SPRING, SUMMER, AUTUMN }; // = 0 by default // = WINTER + 1 // = WINTER + 2 // = WINTER + 3 enum Season curr_season; curr_season= AUTUMN; curr_season= 19; // legal, but ugly, g++: warning int SUMMER; // error, redefinition int prev_season = SUMMER; // legal, but ugly, g++ warning 17

Use enum to eliminate magic numbers – alternative to #define 18

C++-11 enum class Season : char { WINTER, // = 0 by default SPRING, // = WINTER + 1 SUMMER, // = WINTER + 2 AUTUMN // = WINTER + 3 }; Season curr_season; curr_season= Season: : AUTUMN; curr_season= SUMMER; // won’t compile! curr_season= 19; // won’t compile! int prev_season= Season: : SUMMER; // won’t compile! 19

enums – why? More readable code Code less error prone Accessible for debugger Use of the numerical values is not disabled �bad programming usually! 20

Overloading Understand remember. • • 21 More than syntactic sugar. This is how a lot of stuff works under the hood (e. g. inheritance)

Function overloading - C #include <stdio. h> void foo() { printf ("foo()n"); } void foo(int n) { printf ("foo(%d)n", n); } int main() { foo(12); foo(); return 0; } 22 Compilation output: Error: Multiple definition of foo

Function overloading – C++ #include <iostream> void foo() { std: : cout << "foo()n"; } void foo(int n) { std: : cout<<"foo("<<n<<")n"; } int main() { foo(12); foo(); } 23 Output: Compile, and print: foo(12) foo()

Default parameters #include <iostream> void foo(int n=5) { std: : cout<<"foo("<<n<<")n"; } int main() { foo(); foo(42); } 24 Output: Compile, and print: foo(5) foo(42)

Overload resolution 25