Introduction to c programming


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Introduction to c programming

  1. 1. C PROGRAMMING TUTORIAL By: gajendra singh rathore
  2. 2. OUTLINE Overview History Features Role of C Compiler Flowchart Sample C Program 1 Character Set Data Types Variables C is Case Sensitive C Token Sample C Program 2 Control Statements Common Programming Errors 2 Assignment
  3. 3. OVERVIEW OF C C language is  Structured  High level  Machine independent  Follows top down approach 3
  4. 4. HISTORY ALGOL  In 1960’s  First language using a block structure BCPL  In1967  Basic Combined Programming Language B  In1970  Added feature of BCPL 4
  5. 5. CONTD… C  Evolved from ALGOL, BCPL & B  Developed between 1969 and 1973 along with Unix  Developed at AT & T’s Bell Laboratories of USA  Designed and written by Dennis Ritchie 5
  6. 6. FEATURES C is PortableThis means a program written for one computer may run successfully on other computer also. C is fast This means that the executable program obtained after compiling and linking runs very fast. C is compact The statements in C Language are generally 6 short but very powerful.
  7. 7. CONTD… Simple / Easy The C Language has both the simplicity of High Level Language and speed of Low Level Language. So it is also known as Middle Level Language C has only 32 Keywords C Compiler is easily available C has ability to extend itself. Users can add their own 7 functions to the C Library
  8. 8. ROLE OF C COMPILER  Compiler: converts source to object code for a specific platform  Linker: resolves external references and produces the executable module Typically C programs when executing, have four different files  Source Code – file that is created by user and the executable statements are written. This file is saved with a file extension of ‘.c’.  Header files – contains the declaration of functions and pre- processors statements. Header files have ‘.h’ as their extension.  Object files – are the output from the compilers. ‘.o’ or ‘.obj’ are the typical extension to such files. 8  Binary executables – are an output of the process of linking. Binary executables have ‘.exe’ as their extension.
  9. 9. FLOWCHART Flow charts are symbolic diagrams of operations and the sequence, data flow, control flow and processing logic in information processing. These charts are used to understand any working sequence of the program. Flow char is a graphical representation of algorithm. An algorithm defines as the step by step procedure or method that can be carried out for 9 solving programming problems.
  10. 10. CONTD…Advantages of flowchart:- It provides an easy way of communication because any other person besides the programmer can understand the way they are represented. It represents the data flow. It provides a clear overview of the entire program and problem and solution. 10
  11. 11. CONTD… It checks the accuracy in logic flow. It documents the steps followed in an algorithm. It provides the facility for coding. It provides the way of modification of running program. They shows all major elements and their relationship. 11
  13. 13. CONTD… Terminator This symbol represents the beginning and end point in a program. We use start and stop option in it. Input / Output Symbol This symbol is used to take any input or output in the algorithm. Process Symbol A rectangle indicates the processing, calculation 13 and arithmetic operations
  14. 14. CONTD… Decision Symbol It is used when we want to take any decision in the program. Connector Symbol This symbol is used to connect the various portion of a flow chart. This is normally used when the flow chart is split between two pages Data Flow Symbol This symbol is used to display the flow of the 14 program. It shows the path of logic flow in a program.
  15. 15. SAMPLE C PROGRAM main() --------------Function name { ------------Start of Program …. …. -------- Program statements …. } --------------- End of Program 15
  16. 16. CONTD…/* Filename : hello.c Description : This program prints the greeting “Hello, World!”*/ #include <stdio.h> #include <stdio.h> int main(void) void main( ) { { printf ( “Hello, World!n” ) ; printf ( “Hello, World!n”); return 0 ; getch(); } } 16
  17. 17. FLOWCHART FOR HELLO.C An oval denotes either int main () the start or the end of { the program, or a halt printf("Hello, world!n"); } operation within the Start program (which we’ll learn about later). A parallelogram Output “Hello, world!” denotes either an input operation or an output operation. End An arrow denotes the flow of the program. 17
  18. 18. CONTD… Comments  Text surrounded by /* and */ is ignored by computer  Used to describe program int main()  Program’s execution starts from the main function  Parenthesis used to indicate a function  int means that main "returns" an integer value  Braces ({ and }) indicate a block  The bodies of all functions must be contained in braces 18
  19. 19. CONTD…o Preprocessor directives #include <stdio.h> #include <conio.h> #include <stdlib.h> #include <string.h> The #include directives “paste” the contents of the files like stdio.h and conio.h into your source code, at the very place where the directives appear. 19
  20. 20. CONTD… These files contain information about some library functions used in the program:  stdio stands for “standard I/O”,  conio stands for “console I/O”  stdlib stands for “standard library”,  string.h includes useful string manipulation functions. Want to see the files? Look in /TC/include 20
  21. 21. CONTD…#define MAX_COLS 20#define MAX_INPUT 1000 The #define directives perform “global replacements”:  every instance of MAX_COLS is replaced with 20, and every instance of MAX_INPUT is replaced with 1000 21
  22. 22. CONTD… commonly used stdio.h functions: printf() – Output function Syntax: printf(“….”) ; scanf() – Input function Syntax: scanf(“format specifier”, &var,&var2…); 22
  23. 23. CONTD… commonly used conio.h functions: clrscr() Used to clear the screen getch() Used to get a character from ouput screen to come into the edit screen. 23
  24. 24. CHARACTER SETThese are the characters that C recognizes.Letters (upper case and lower case)AB C DE F G H I J KLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzDigits0123456789 Special Characters (punctuation etc)space (also known as blank)’" ( ) * + - / : =!&$;<>%?,.ˆ#@˜‘{}[]| 24
  25. 25. CONTD… 256 characters are allowed in C. A – Z : 65 to 90 26 a – z : 97 to 122 26 0 – 9 : 48 to 57 10  Special symbols[ #, &, `…] 32  Control characters[n, t . ..] 34  Graphic characters 128 Total 256 25
  26. 26. DATA TYPESo C support several different types of data, which may berepresented differently within the computers memory.o Types 1] Primary 2] Derived 3] User Defined  Integer  Arrays  typedef  Float  Pointers  enum  Double  Structure  Character 26
  27. 27. CONTD… Primary Data TypesData Types Byte Format Specifier1] char 1 %c signed char 1 %c unsigned char 1 %c2] short 2 %d short signed int 2 %d short unsigned int 2 %u3] int 2 %d 27 signed int 2 %d unsigned int 2 %u
  28. 28. CONTD…Data Types Byte Format Specifier4] long 4 %l long signed int 4 %ld long unsigned int 4 %lu5] float 4 %f signed float 4 %f unsigned float 4 %uf6] double 8 %lf 287] Long Double 10 %Lf
  29. 29. TYPE CASTING It is used to convert on data at a time. We can have two types of type casting.  Implicit  Explicit  Implicit : This converts narrow type to wider type so that user can avoid the information to the system. Explicit : Explicit type casting is done by the programmer manually. When the programmer wants a result of an expression to be in particular type, then we use explicit type casting. This type casting is done by casting operators ‘( )’ 29 and data type.
  30. 30. CONTD…#include <stdio.h>void main( ){ int base, height, area; base = 5; height =3; area = (base * height)/2; printf ( “Area = %d n”, area);}Output : Area = 7 ……………………. Incorrect 30
  31. 31. CONTD…#include <stdio.h>void main( ){ int base, height, area; base = 5; height = 3; area = ((float) (base * height)/2); printf ( “Area = %d n”, area);}Output : Area = 7.5 …………………….Correct 31
  32. 32. USER DEFINED DATA TYPE[A] Type Definition Allows user to define an identifier that would represent an existing data type Syntax: typedef type identifier Eg: typedef int units; units batch1, batch2; 32
  33. 33. CONTD…[B] Enumerated data type Syntax: enum identifier { value1, value2... valuen} Eg: enum day{ Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday} 33
  34. 34. VARIABLES Variable names correspond to locations in the computers memory Data name that may be used to store a data value It may take different values at different times during execution Eg:  char x;  char y = ‘e’; 34
  35. 35. CONTD… Rules  Must begin with a letter(), some system permits underscore as first character.  Length should be not more than 8 characters  Uppercase and lowercase are significant, (i.e.) total and TOTAL are different  Variable should not be a keyword  White space is not allowed 35
  36. 36. C IS CASE SENSITIVEC is case sensitive: it distinguishes between UPPER case (CAPITAL) and lower case (small) letters.Keywords in C — for example, the keyword int — MUST be in lower case. For example:#include <stdio.h> int main () { /* main */ int height_in_cm; height_in_cm = 160; printf("My height is %d cm.n",height_in_cm);} /* main */ 36
  37. 37. C TOKENS  Keywords  Identifiers  Constants  Strings  Special Symbol  Operators 37
  38. 38. CONTD… Keywords  C uses 32 keyword  have fixed meaning and cannot be changedKeywordsauto double int structbreak else long switchcase enum register typedefchar extern return unionconst float short unsignedcontinue for signed voiddefault goto sizeof volatiledo if static while 38
  39. 39. CONTD… Constants  Quantity that does not change is called a constant.  Types  Numeric constants  Integer constants – 123, -33  Real constants – 0.992, 3.5e2  Character constants  Single character constants – ‘5’, ‘a’  String Constants – ‘Hello’, ‘1999’ 39
  40. 40. CONTD…Backslash Characters Constants n – Newline b – Backspace f – Form feed t – Tab or horizontal tab a – Audible alert r – Carriage return v – Vertical Tab ’ – Single Quote ” – Double Quote ? – Question Mark - Backslash 40 0 - Null
  41. 41. CONTD… Identifiers Names of arrays, function and variable Operators Arithmetic Relational Logical Bitwise 41
  42. 42. CONTD….ARITHMETIC OPERATORSC operation Arithmetic Algebraic C expression operator expressionAddition + f+7 f+7Subtraction - p–c p-cMultiplication * bm b*mDivision / x/y x/yModulus % r mod s r % s 42
  43. 43. CONTD…. Equality and Relational Operators Standard algebraic C equality or Example of C Meaning of C equality operator or relational condition condition relational operator operator E quality O perators = == x == y x is equal to y not = != x != y x is not equal to y R ela tiona l Op erators > > x > y x is greater than y < < x < y x is less than y >= >= x >= y x is greater than or equal to y <= <= x <= y x is less than or 43 equal to y
  44. 44. CONTD…. Logical Operators:  && logical And  || logical Or  ! logical Not Bitwise Operators & bitwise And  | bitwise Or  ^ bitwise Xor  ~ bitwise Not  << shift left  >> shift right 44
  45. 45. SAMPLE C PROGRAM 2/* Program for multiplication of two variables */#include<stdio.h>#include <conio.h>void main(){int a,b,c;clrscr();printf(“Enter two numbers”);scanf(“%d%d”,&var1,&var2);c=a*b;printf (“n Multiplication of two numbers is %d ”,c);getch(); 45}
  46. 46. CONTD… OUTPUT: Enter two numbers: 12 3 Multiplication of two numbers is 36 46
  47. 47. CONTROL STATEMENTS These statements are used to control the flow of program by using these statements. We can have four types of control statements:- decision making case control statement or switch statement looping / iteration statement jump / branching statement 47
  48. 48. DECISION MAKING These statements are used when we want to take any decision according to the condition or user requirement. These conditions are used by using ‘if’ statement. We can have four types of conditional statements if if-else if – else if nested if 48
  49. 49. CONTD…. if if statement is simple decision making statement, which is used to take any decision when the condition is true. if (statement) { Statement; } if (expression / condition) Statement; 49
  50. 50. CONTD…. If-else This statement is used to make decision in C language. If the given condition is true then the cursor will move to the true portion else it will move to the false portion. if (condition) {Statement;}else{ 50Statement;}
  51. 51.  If else-if if (condition) { Statement; } else if (condition) { Statement; } else if (condition) { Statement; } else { 51 Statement;
  52. 52. SWITCH CASE / SELECT CASE These statements are used with the replacement of if-else and these statements are used when we have multiple options or choices. These choices can be limited and when we use switch case we can use only integer or character variable as expression. 52
  53. 53.  Syntax: switch( expression){ case value-1: block-1; break; case value-2: block-2; break;---- default: default-block; break; 53}statement -X;
  54. 54. LOOPING These statements are used to control the flow of the program and repeat any process multiple times according to user’s requirement. We can have three types of looping control statements. while do-while 54 for
  55. 55. CONTD…While It is an entry control loop statement, because it checks the condition first and then if the condition is true the statements given in while loop will be executed. SYNTAX:- Initialization; while (condition) { Statements; Incremental / decrement; 55 }
  56. 56. CONTD…Do-while Do-while loop is also called exit control loop. It is different from while loop because in this loop the portion of the loop is executed minimum once and then at the end of the loop the condition is being checked and if the value of any given condition is true or false the structure of the loop is executed and the condition is checked after the completion of true body part of the loop. 56
  57. 57. CONTD… SYNTAX:- Initialization do { Statement; Increment / decrement; } while (condition) 57
  58. 58. CONTD….For loop It is another looping statement or construct used to repeat any process according to user requirement but it is different from while and do- while loop because in this loop all the three steps of constructions of a loop are contained in single statement. It is also an entry control loop. We can have three syntaxes to create for loop:- 58
  59. 59. CONTD….for (initialization; Test condition; Increment / decrement) { Statement; }…………………………………….for (; test condition; increment / decrement) { Statement; } 59………………………………………
  60. 60. CONTD….for (; test condition;) { Statement; Increment / decrement } 60
  61. 61. JUMPS STATEMENTS These are also called as branching statements. These statements transfer control to another part of the program. When we want to break any loop condition or to continue any loop with skipping any values then we use these statements. There are three types of jumps statements. Continue Break 61 Goto
  62. 62. CONTD… Continue This statement is used within the body of the loop. The continue statement moves control in the beginning of the loop means to say that is used to skip any particular output. WAP to print series from 1 to 10 and skip only 5 and 7.#includevoid main ( ){ 62int a;
  63. 63. CONTD…clrscr ( );for (a=1; a<=10; a++){if (a= =5 | | a= = 7)continue;printf (“%d n”,a);}getch ( );} 63
  64. 64. CONTD…Break This statement is used to terminate any sequence or sequence of statement in switch statement. This statement enforce indicate termination. In a loop when a break statement is in computer the loop is terminated and a cursor moves to the next statement or block; Example: WAP to print series from 1 to 10 and break on 5 #include 64 void main ( ) {
  65. 65. CONTD…int a;clrscr ( );for (a=1; a<=10; a++){if (a= =5)break;printf (“%d n”,a);}getch ( );} 65
  66. 66. CONTD…Goto statement It is used to alter or modify the normal sequence of program execution by transferring the control to some other parts of the program. the control may be move or transferred to any part of the program when we use goto statement we have to use a label. Syntax: Forward Loop: goto label; …. …. 66 label: statement;
  67. 67. CONTD… Backward Loop: label: statement …. …. goto label; 67
  68. 68. COMMON PROGRAMMINGERRORS Missing Semicolons  Eg: a = x+y …… is wrong c= b/d; …… is right Misuse of Semicolon  Eg: for(i = 1; i <= 10; i++); sum = sum + i;  is wrong for(i = 1; i <= 10; i++) sum = sum + i; 68  is right
  69. 69. CONTD…  Use of = instead of = =  Missing Braces  Missing Quotes  Improper Comment Characters  Undeclared Variables And many more…… 69
  70. 70. ASSIGNMENT Write a C program to swap two entered number. Write a C program to perform all the arithmetic operations. Write a C program to find the area of a circle, triangle and rectangle. Write a C program to calculate the area of circle, triangle and rectangle. Write a C program to get a number from user 70 and print a square and cube of that number.
  71. 71. CONTD… Write a C program to display the greatest of three number using if else statement. Write a C program to find the number is positive or negative. Write a C program to find the number is odd or even. Write a program to display the spelling of number using switch case. 71
  72. 72. CONTD… Write a C program to display the entered letter is vowel or a character. Write a C program to display odd number from 1 to n using while loop and do while loop. Write a C program to display even number from 1 to n using for loop. 72
  73. 73. QUERIES? 73
  74. 74. THANK YOU!!! 74