Unit 2 Elements of C.pptx
- 1. Dinesh Maharjan, 2022 Programming in C Elements of C Instructor: Dinesh Maharjan 2022
- 2. • C was introduced by Brian Kernighan and Dennis Ritchie in 1978 to develop unix operating system at Bell Labs. • This version of C is known as K&R C (1972-1989). • Essentially all unix applications are written in C. • C is a successor of B language. • C is portable. • C programs are as fast as the assembly programs • C is widely used as the system programming language C Introduction
- 3. • C has now become a widely used professional language for • Easy to learn • Structured language • Can be compiled on variety of computers. • C uses low level features such as chracters, numbers and addresses. • C operators does not work on composite data types such as strings, arrays, sets C Introduction
- 5. • Initially, C is known as K&R C (1972-1989). • Later it was standardized by ANSI in 1989 known as ANSI- C or C89. • C was internationally accepted and was standardized by ISO in 1990 known as The C language or C90. • Minor update was released in 1995 as C95. • C99 was released in 1999 with major revision. • C11 was released in 2011 with major focus in multi- core, multi-processing and expression sequencing. C Standard
- 6. GNU C Compiler (GCC) • For compiling C language, we need C compiler. • GNU C Compiler can be used by installing MinGW. • You should add the path of bin subdirectory of MinGW installation to PATH environmental variable.
- 7. GNU C Compiler (GCC) • To run the executable, type a
- 8. GNU C Compiler (GCC)
- 10. Tokens • Building Blocks of C language • Includes keywords, identifiers, constant, operators, special symbols
- 16. Unary Operator ++, -- Unary Operator Binary operator +, -, *, /, % Arithmetic Operator <, <=, >, >=,==, != Relational Operator &&, !!, ! Logical Operator &, |, <<, >>, ~, ^ Bitwise Operator =, +=, -=, *=, /=, %= Assignment Operator Ternary Operator ?: Conditional Operator
- 34. • Special Symbols that separate variables, constants or statements • (,) comma separates variables and constant • ( spacebar) separates keywords, expression • (;) semicolon separates or ends the statement. Delimiters
- 35. • Instruction to the computer to do certain task. • Usually one statement per line. • It can span over multiple lines. • Ends with ; (Semicolon) • It is combination of keywords, expression • X=5*2; • printf(“Let C”); Statement
- 36. • Compiler ignores white spaces in the statement. • However white spaces within a string constant is not ignored. Statement
- 37. Statement
- 38. Types of Statement • Simple statement: x=5+9; • Null statement: ; • Compound Statement: • { • X=4+8; • Y=9+9; • }
- 39. Expression • Combination of operand, operator and function. • Expression evaluates to some value that can be numeric or string. • 4+9 • “b”+”C”
- 40. Comments • Make programs easy to read and modify. • Comments are removed by compiler before generating executable. • Comments is kept inside /* comment */ • It can be multiple lines also.
- 41. Structure of a C program • Preprocessor • Comments • Function Prototype • Main function • The return type of main function must be int. • K&R C supports main() without return type. • Main without return type is defaulted int return type. • Most of compilers does not support void return type.
- 42. #include <stdio.h> // program prints hello world int main() { printf ("Hello world!"); return 0; } Output: Hello world!