C Language
What is C ?
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Is a general-purpose computer programming language.
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A High-level language.
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It is the most widely used computer.
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Mother of all modern languages.
History
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It was created in 1972.
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Developed by Dennis Ritchie.
Why C
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Produce efficient programs.
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Can be compiled on a variety of computer platforms.
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Structured language.
Environment Setup
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By downloading any IDE for C program comes with build in the environment.
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Here, to set up a C program environment, we need to have 2 software:
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Text Editor (Sublime Text 3)
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C Compiler (GNU Compiler)
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Compiler
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A compiler translates programing language into executable code.
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Programming languages may be any high-level language (eg. C, C++, Java, C#, Python)
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Here we will have C compiler for executing .c file.
High-level Language
#include <stdio.h>
int main()
{
print ("Hello!/n")
}
demo.c
Machine-level Language
Compiler
0101010101011000101000010101010010101001001001001
demo.exe
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To install GCC compiler, go to MinGW.org > download & install the compiler.
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Make the bin directory as PATH for the PC.
The Hello World
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Here is the Hello World program of C program with the minimum code as extension filename.c
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Open the command prompt > go to the .c file directory
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Type gcc helloSPS.c to compile.
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It will generate the a.exe file on the same directory.
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Type a to execute the program on the screen.
To compile helloSPS.c file
To execute the a.exe file
Here is the output
.exe file
.c file
Compiler on Sublime Text
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Instead of writing commands lime for executing C programs, we can make Sublime Text editor do itself.
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On Sublime Text option > Tools > Build System > New Build Path > paste the Jason code for GCC compiler > save as C.
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Now we can compile & execute a C program by hitting Ctrl + B .
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Here are gif shows how we made it.
C Syntax
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The above program has the basic syntax of C language
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Following are the description:
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#include <stdio.h>: it includes standard input outpur library function.( eg printf(), scanf() )
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int main (): Every c programs has a main funcion to execute.
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printf(): A funtion used to print on console.
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return 0: Returns execution status to OS (0 or 1).
Variable in C
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With variable we can store a data.
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Variable stores on memory location.
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One should declare a variable with datatype.
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Here are some rules for declaring & defined variable with syntax.
Datatype
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Datatype means the types of data that can store on a variable.
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Eg. Integer, Floating, Sting etc.
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In C, There are 4 types of a datatype.
Basic
int, char, float, double
Derived
Datatype
array, pointer, structure, union
Enumeration
enum
Void
non return type
Printf & Scanf
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Both are the in-build function from stdio.h header file.
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The printf() is used for output.
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The scanf() is used for taking user input.
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Both functions have a statement to print the which type of variable with a variable.
Format Specifier
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Format specifier are used to take the input & output.
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It says which type of data is in variable using scanf( ) & printf( )
Control Statement
If Else
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The block of code will be executed according to a basic condition.
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In C, there are statements available such as; if , if else, if else-if.
Do While
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While loop is used to execute part of code multiple time untill condition is false.
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The do-while loop is similar to While loop but at least execute once regardless of condtion.
For Loop
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To iterate the code several time with condition and increment/decrement function.
Switch Case
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Like if else-if ladder statement, the block of code from multiple conditions.
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The switch expression and case value must be of integer or character type.
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Every case should have break or goto keyword else it will follow fall-through condition.
Scope in Variable
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Global Variable: Accessible throughout the program.
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Local Variable: Accessible only inside of the program.
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Formal Variable: While passing an argument with a function.
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There are 4 storage classes used for defining the scope and lifetime of a variable.
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These following keywords are used:
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auto: Default storage class, applied to all local variables automatically.
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register: Allocates memory in register than RAM, faster access than other variables.
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extern: Visible to all the programs.
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static: Once initialized, exists until the end of the program.
Pointer
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Pointer stores the value of address of another variable & points toward it.
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We need to declare a pointer before use.
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Pointer datatype should be the same as the pointing variable.
String
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It is an array of character terminated by a null character.
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We can declare a string with char keyword with or without array size.
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Here is the 2 way of initializing the char.
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char array
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string literal
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In C program, there is a lot of function for string manipulation.
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Some of them are in below table.
Structure in C
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Structure in C is a user-defined datatype.
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Each element it stores is called a member.
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Here, struct keyword is used to declare a structure.
File Handling
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In C, there is some specific function to handle files on local disk.
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The file may be of two types:
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Text files ( .txt )
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Binary files ( .bin )
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To communicate with file and program, we need to declare a pointer of a datatype.
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fopen() is a library function in stdio.h header file with file name & read/write mode.
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To work with the file, there are some several steps we need to follow.
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Creating a new file with a pointer
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Opening a file
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Reading/Writing to a file
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Closing a file
Write a File
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For reading a file, we use fprintf() & fwrite() functions.
Read a File
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For reading a file, we use fscanf() & fread( ) functions.
Graphics in C
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For drawing different shapes, fonts & colors, we use a graphics.h header file.
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graphics.h contains lots of pre-defined functions to implement Graphical User Interface.
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We can make graphics programs, animation & games.
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Here is some functions from graphics.h header.
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arc
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bar
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cricle
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line
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rectangle
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ellipse
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outtext
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textwidth
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Drawing in C
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With graphics.h functions, we can draw circle, lines, rectangles, bars & other geometrical figures.
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Below program is for drawing a some geometrical shapes.
C with MySQL
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There are several APIs available in internet allows us to interact with different databases
- We need to download the correspondence APIs which contains header file.
- And that header file should be kept in compiler's include folder to be accessed.
Incule mysql.h
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Here we used mysql.h header file to interact MySQL database.
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We downloaded & mysql.h and kept in complir's include folder.
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Above picture shows where all the header path presents.
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Download mysql.h file
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keep in compiler's include folder
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The above header file has lots of functions regarding MySQL.
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Below program is the example of database connection.
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The codes can be divided into 4 parts:
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Initiation of a connection handle stucture
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Creation of a connection
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Execution of a query
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Closing of connection
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Program 1
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WAP to ask username & his age, then write a sentence.
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Input: Ravi
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Output: 18
Program 2
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Find the Permutation of string.
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Input: ab
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Output: ab, ba
Program 3
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Find Digit Identification if the string has any number.
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Input: Stone123Profits
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Output: True, if the string contains a number; False, if the string contains a number
Program 4
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Find and Replace the 1st highest repeated character with user given character.
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Input: abcabab
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Output: pbcpbpb
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The out put of above program asks the user to enter a String & a character to replace with the highest repeated character.
Compiles the program
Executing the program
Asks user to enter a String
Asks user to enter a Char
OUTPUT
Program 5
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Write a program to print Diamond pattern.
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Input: 5
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Output: pattern
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The above program prints the given diamond pattern on command prompt.
Compiles .c file
OUTPUT
Type a for executing above program
Program 6
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Write a program to sum the numbers in a string.
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Input: stone123profits7
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Output: 130
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In command prompt, we compile & executed the FindSumNumbersFromString.c file.
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We used gcc command for compiling & a for executing the c file.
Compils .c file
OUTPUT
Ask user to input