C basics 4 std11(GujBoard)

Chapter 3: Introduction to C Programming Language,[object Object],C development environment,[object Object],A simple program example,[object Object],Characters and tokens,[object Object],Structure of a C program,[object Object],comment and preprocessor directives,[object Object],basic data types,[object Object],data declarations,[object Object],statements,[object Object],Basic functions,[object Object]

Program is,[object Object],created in the,[object Object],Editor and ,[object Object],stored on Disk.,[object Object], Editor,[object Object],Phase 1 :,[object Object],Disk,[object Object],Disk,[object Object],Compiler ,[object Object],creates object,[object Object],code and stores ,[object Object],it on Disk.,[object Object],Compiler,[object Object],Phase 3 :,[object Object],Disk,[object Object],Linker links object ,[object Object],code with libraries, ,[object Object],creates a.out and ,[object Object],stores it on Disk.,[object Object], Linker,[object Object], Phase 4 :,[object Object],Disk,[object Object],C Development Environment,[object Object],Preprocessor,[object Object],program,[object Object],processes the ,[object Object],code.,[object Object], Preprocessor,[object Object],Phase 2 :,[object Object]

Primary,[object Object], Memory,[object Object],Loader,[object Object], Phase 5 :,[object Object],Loader puts,[object Object],Program in,[object Object],Memory,[object Object],:,[object Object],.,[object Object],Primary,[object Object], Memory,[object Object],C P U,[object Object],Phase 6 :,[object Object],CPU takes each,[object Object],instruction and ,[object Object],executes it, storing,[object Object],new data values as,[object Object],the program executes.,[object Object],:,[object Object],.,[object Object]

From code to executables,[object Object],Source Code,[object Object],Pre-processor,[object Object], Compiler,[object Object],Assembly Code,[object Object], Assembler,[object Object],Libraries,[object Object], Object Code,[object Object], Linker,[object Object], Executable Code,[object Object]

A Simple Program Example,[object Object],#include <stdio.h>,[object Object],main(),[object Object],{,[object Object], printf("Programming in C is easy.");,[object Object],},[object Object],Sample Program Output,[object Object],Programming in C is easy.,[object Object]

[object Object],In C, lowercase and uppercase characters are very important! All commands in C must be lowercase. The C programs starting point is identified by the word ,[object Object], main(),[object Object], This informs the computer as to where the program actually starts. The brackets that follow the keyword main indicate that there are no arguments supplied to this program (this will be examined later on).,[object Object], The two braces, { and }, signify the begin and end segments of the program. ,[object Object]

The purpose of the statement,[object Object], #include <stdio.h>,[object Object], is to allow the use of the printf statement to provide program output. Text to be displayed by printf() must be enclosed in double quotes. The program has only one statement ,[object Object], printf("Programming in C is easy.");,[object Object], printf() is actually a function (procedure) in C that is used for printing variables and text. Where text appears in double quotes "", it is printed without modification. There are some exceptions however.,[object Object]

This has to do with the and % characters. These characters are modifiers, and for the present the followed by the n character represents a newline character. ,[object Object], Thus the program prints,[object Object],Programming in C is easy.,[object Object],and the cursor is set to the beginning of the next line. As we shall see later on, what follows the character will determine what is printed, ie, a tab, clear screen, clear line etc. Another important thing to remember is that all C statements are terminated by a semi-colon ; ,[object Object]

program execution begins at main()

keywords are written in lower-case

statements are terminated with a semi-colon

text strings are enclosed in double quotes,[object Object]

A token is a language element that can be used in forming higher level language constructs,[object Object],Equivalent to a ‘word’ in English language,[object Object],Several types of tokens can be used to build a higher level C language construct such as expressions and statements,[object Object],There are 6 kinds of tokens in C:,[object Object],Reserved words (keywords),[object Object],Identifiers,[object Object],Constants,[object Object],String literals,[object Object],Punctuators,[object Object],Operators,[object Object]

Reserved Words,[object Object],Keywords that identify language entities such as statements, data types, language attributes, etc.,[object Object],Have special meaning to the compiler, cannot be used as identifiers in our program.,[object Object],Should be typed in lowercase.,[object Object],Example: const, double, int, main, void, while, for, else (etc..),[object Object]

Identifiers,[object Object],Words used to represent certain program entities (program variables, function names, etc).,[object Object],Example:,[object Object],int my_name; ,[object Object],my_name is an identifier used as a program variable,[object Object],void CalculateTotal(int value),[object Object],CalculateTotal is an identifier used as a function name,[object Object]

Constants,[object Object],Entities that appear in the program code as fixed values.,[object Object],4 types of constants:,[object Object],Integer constants,[object Object],Positive or negative whole numbers with no fractional part,[object Object],Example: ,[object Object],const int MAX_NUM = 10;,[object Object],const int MIN_NUM = -90;,[object Object],Floating-point constants,[object Object],Positive or negative decimal numbers with an integer part, a decimal point and a fractional part,[object Object],Example:,[object Object],const double VAL = 0.5877e2; (stands for 0.5877 x 102),[object Object]

Character constants,[object Object],A character enclosed in a single quotation mark,[object Object],Example:,[object Object],const char letter = ‘n’;,[object Object],const char number = ‘1’;,[object Object],printf(“%c”, ‘S’);,[object Object],Output would be: S,[object Object],Enumeration,[object Object],Values are given as a list,[object Object],Example:,[object Object]

String Literals,[object Object],A sequence of any number of characters surrounded by double quotation marks. ,[object Object],Example:,[object Object],“REFORMASI”,[object Object],“My name is Salman”,[object Object],Example of usage in C program:,[object Object],printf(“My room number is BN-1-012”);,[object Object],Output: My room number is BN-1-012,[object Object]

Punctuators (separators),[object Object],Symbols used to separate different parts of the C program.,[object Object],These punctuators include:,[object Object],[ ] ( ) { } , ; “: * #,[object Object],Usage example:,[object Object]

Operators,[object Object],Tokens that result in some kind of computation or action when applied to variables or or other elements in an expression.,[object Object],Example of operators:,[object Object],* + = - /,[object Object],Usage example:,[object Object],result = total1 + total2;,[object Object]

Structure of a C program,[object Object],Preprocessor directive (header file),[object Object],Program statement,[object Object],},[object Object],Preprocessor directive,[object Object],Global variable declaration,[object Object],Comments,[object Object],Local variable declaration,[object Object],Variable definition,[object Object]

Comments,[object Object],Explanations or annotations that are included in a program for documentation and clarification purpose.,[object Object],Completely ignored by the compiler during compilation and have no effect on program execution.,[object Object],Starts with ‘/*’ and ends with ‘*/’,[object Object],Some compiler support comments starting with ‘//’,[object Object]

Preprocessor Directives,[object Object],The first thing to be checked by the compiler.,[object Object],Starts with ‘#’.,[object Object],Tell the compiler about specific options that it needs to be aware of during compilation.,[object Object],There are a few compiler directives. But only 2 of them will be discussed here.,[object Object],#include <stdio.h>,[object Object],Tell the compiler to include the file stdio.h during compilation,[object Object],Anything in the header file is considered a part of the program,[object Object],#define VALUE 10,[object Object],Tell the compiler to substitute the word VALUE with 10 during compilation,[object Object]

Basic Data Types,[object Object],3 examples of basic data types:,[object Object],int (used to declare numeric program variables of integer type),[object Object],char (used to declare character variable),[object Object],double (used to declare floating point variable),[object Object],In addition, there are float, void, short, long, etc.,[object Object],Declaration: specifies the type of a variable.,[object Object],Example: int local_var;,[object Object],Definition: assigning a value to the declared variable.,[object Object],Example: local_var = 5;,[object Object]

A variable can be declared globally or locally.,[object Object],A globally declared variable can be accessed from all parts of the program.,[object Object],A locally declared variable can only be accessed from inside the function in which the variable is declared.,[object Object]

Statements,[object Object],A specification of an action to be taken by the computer as the program executes.,[object Object],In the previous example, there are 2 lines following variable declaration and variable definition that terminate with semicolon ‘;’. ,[object Object],global_var = local_var + VALUE;,[object Object],printf (“Total sum is: %d”, global_var);,[object Object],Each line is a statement.,[object Object]

Basic Functions,[object Object],A C program consists of one or more functions that contain a group of statements which perform a specific task.,[object Object],A C program must at least have one function: the function main.,[object Object],We can create our own function or use the functions that has been created in the library, in which case we have to include the appropriate header file (example: stdio.h).,[object Object]

In this section, we will learn a few functions that are pre-defined in the header file stdio.h,[object Object],These functions are:,[object Object],printf(),[object Object],scanf(),[object Object],getchar() & putchar(),[object Object], In addition to those functions, we will also learn about Format Specifier and Escape Sequence which are used with printf() and scanf().,[object Object]

printf(),[object Object],Used to send data to the standard output (usually the monitor) to be printed according to specific format.,[object Object],General format:,[object Object],printf(“control string”, variables);,[object Object],Control string is a combination of text, format specifier and escape sequence.,[object Object],Example:,[object Object],printf(“Thank you”);,[object Object],printf (“Total sum is: %d”, global_var);,[object Object],%d is a format specifier,[object Object], is an escape sequence,[object Object]

Format Specifier,[object Object],Tells the printf() function the format of the output to be printed put.,[object Object]

C basics 4 std11(GujBoard)

C basics 4 std11(GujBoard)

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C basics 4 std11(GujBoard)