Cpp
- 1. BASICS OF C++ BY ANANTHU G College of Engineering Perumon
- 2. Introduction Why using C++ ? ANSI Standard. Compilers available on all platforms. All libraries consits of c or c++ API . Is C++ better than Fortran ? Struture Object orientation Error checking during compiling 2
- 3. ╺ In 1979, Bjarne Stroustrup, a Danish computer scientist, began work on "C with Classes", the predecessor to C++. ╺ Started in 1978 and released the first version in 1979 at AT and T Bell Labs. ╺ In 1983 it was named as C++. ╺ The C++ is also the 4th most used language. 3 HISTORY OF C++
- 4. C++ Program Fomat #include <iostream.h> // preprocessor directive or header files #include<conio.h> // preprocessor directive void main() { // statement block enclosed by { and } clrscr(); // clears the output screen cout << "Hello World"; // prints Hello World getch(); // get a character to terminate from output screen endl:} //either endl or return 0 can be used to end the program All c++ programs have only one main function. It can either return as void main() or int main() 4
- 5. C Language •Designed by Dennis Ritchie •Appeared in1972 •Language TypeProcedural Oriented Language •Execution Flow Top to Bottom Comparison C and C++ C++ Language •Designed by Bjarne Stroustrup • Appeared in1985 •Language Type Multi-Paradigm Object Oriented Language •Execution Flow Top to Bottom 5
- 6. Data Types in C++ Data Type ╺ Boolean ╺ Character ╺ Integer ╺ Floating point ╺ Double floating point ╺ Valueless Keyword ╺ bool ( 1 bit) ╺ char ( 1 bit) ╺ int (4 bit) ╺ float ( 4 bit) ╺ double ( 8 bit) ╺ void 6
- 7. Functions ╺ In programming, function refers to a segment that groups code to perform a specific task. ╺ Depending on whether a function is predefined or created by programmer; there are two types of function: Library Function User-defined Function 7
- 8. Library Function Library functions are the built-in function in C++ programming. Programmer can use library function by invoking function directly; they don't need to write it themselves. 8
- 9. User-defined Function C++ allows programmer to define their own function. A user-defined function groups code to perform a specific task and that group of code is given a name(identifier). When the function is invoked from any part of program, it all executes the codes defined in the body of function. 9
- 10. Function prototype (declaration) If a user-defined function is defined after main() function, compiler will show error. It is because compiler is unaware of user-defined function, types of argument passed to function and return type. In C++, function prototype is a declaration of function without its body to give compiler information about user-defined function. Function prototype in the above example is: int add(int, int); You can see that, there is no body of function in prototype. Also, there are only return type of arguments but no arguments. You can also declare function prototype as below but it's not necessary to write arguments. int add(int a, int b); Note: It is not necessary to define prototype if user-defined function exists before main() function. 10
- 11. Function Definition The function itself is referred as function definition. Function definition in the above program is: // Function definition int add(int a,int b) { int add; add = a + b; return add; } When the function is called, control is transferred to the first statement of the function body. Then, other statements in function body are executed sequentially. When all codes inside function definition is executed, control of program moves to the calling program. 11
- 12. Function Call To execute the codes of function body, the user-defined function needs to be invoked(called). In the above program, add(num1,num2); inside main() function calls the user- defined function. The function returns an integer which is stored in variable add. 12
- 13. Local Variables Variables that are declared inside a function or block are local variables. They can be used only by statements that are inside that function or block of code. Local variables are not known to functions outside their own. Global Variables Global variables are defined outside of all the functions, usually on top of the program. The global variables will hold their value throughout the life-time of your program. A global variable can be accessed by any function. That is, a global variable is available for use throughout your entire program after its declaration. 13
- 14. Thanks! Any questions? You can find me at ananthuachu444@gmail.com 14