Session 1

| Basics of C Session 1 Objectives Differentiate between Command, Program and Software Explain the beginning of C Explain when and why is C used Discuss the C program structure Discuss algorithms Draw flowcharts List the symbols used in flowcharts Software, Program and Command Software Program 2 Program 1 Commands Commands Commands The Beginning of C C – Dennis Ritchie B – Ken Thompson BPCL – Martin Richards Application Areas Of C C was initially used for systems programming A system program forms a portion of the operating system of the computer or its support utilities Operating Systems, Interpreters, Editors, Assembly programs are usually called system programs The UNIX operating system was developed using C There are C compilers available for almost all types of PC’s Middle Level Language High Level Language Assembly Language C Structured Language C allows compartmentalization of code and data It refers to the ability to section off and hide all information and instructions, necessary to perform a specific task, from the rest of the program Code can be compartmentalized in C by using functions or code blocks. About C C has 32 keywords These keywords combined with a formal syntax form a C programming language Rules to be followed for all programs written in C: All keywords are lowercased C is case sensitive, do while is different from DO WHILE Keywords cannot be used as a variable or function name main() { /* This is a sample Program*/ int i,j; i=100; j=200; : } The C Program Structure-1 main() Delimiters { . } The C Program Structure-2 Statement Terminator ; The C Program Structure-3 /* Comment Lines */ The C Program Structure-4 The C Library All C compilers come with a standard library of functions A function written by a programmer can be placed in the library and used when required Some compilers allow functions to be added in the standard library Some compilers require a separate library to be created Compiling & Running A Program The

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