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Pps Module 1

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70 views20 pages

Pps Module 1

Uploaded by

Priyansh Thakur
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method of describing computer algorithms using a g g ing language. Js an intermittent step towards the development of th ItallowS the programmer to formulate their thoughts on the organization sequence of a computer algorithm without the need for actually following the exact coding syntax. Although pseudocode is frequently used there are no set of rules for its exaet implementation. In general, here are some rules that are frequently followed when writing pseudocode: The usual Fortran symobols are used for arithmetic operations (~~ +1, **) Symbolic names are used to indicate the quantities being processed * Gertain Fortran keywords can be used, such as PRINT, WRITE, READ, ete. | Indentation should be used to indicate branches and loops of instruction. Here is an example problem, including a flowchart, pseudocode, Pseudocode: Input: An integer Limit ‘Ouput: Two integers: Number and Sun by one, ‘Sum and set equal to Sum. rr anez ~ . ee egmmine eegeinee 1 \ Omit-4 oe Topie: Programming Basi : Structure of C program, Syntax , errors STRUCTURE OF A C PROGRAM e structure of a C program is a protocol (rules) to the ich he ha ram is a protocol (1 programmer,-sehich fol ig a C program. The gencial basic structure of C program is shown in the Thee belo ‘Geaumetiatons) ain ¢ Local siacterations: EiSSrem otoremonte Sey er the Coting ner denned tuncton= (option te user) al : ieee nee eer Jf comonte need Bused on this structure, we can sketch a C program. Example: /* This program accepts a number & displays it to the user*/ #include void main(void) {int number; printf{ "Please enter a number: scanf{ "%di", &nummber ); printf "You entered %d", number ); return 0; i Stepwise explanation: #include The part of the compiler whic) ‘preprocessor. #include a rogram, but instead it is an instruction dinelude is a prscprocessor dirctive,'t is not really part of our p: ‘10 the compiler to make if do something, It tells the C compiler to include the contents of a file (in hy. this case the system file called stdic ‘The compiler knows it is a system file, and therefore must be looked for in a special place, by the fact that the filename is enclosed in <> characters stdio.h is the name of the standard library definition file for all Standard Input and Output functions. Your program will almost certainly want to send information to the screen and read things from the ieeyboard, and stdio.h is the name ofthe file in which the funetions that we want fo ust Ret defined. “The favction we want fo use is called printf, The eotual code of printf wil be tied in tater by the linker. ‘The "h portion of the filename is the language extension, which denotes an include file. void This literally means that this means nothing. In this ease, itis referring to the function whose name follows.Void tells (0 C compiler that a given entity has no meaning, and produces no error, Main In this pavticular example, the only function in the program is ealled main. A C programy is typically made up of large nuraber of functions. Each of these is given a name by the programmer and they refer to each other as the program runs.C regards the name main as 9 special case and will ee h actually gets your program from the source file is called the Data Type Inthe C programming language, data_types refer to_a_domain of allowed values & the operations that can be performe Fortes valies, The type of a variable determines how Fach space it occupies in storage and how the bit pattern stored is interpreted: There are 4 = Char is used tp store any fundamental data types in C. which are- char, int, float &, doub! fe character: int is used to store any integer valu, float is used to store any sin any double precision floating sin precision floating point number & double is used to store Boint number We can use 2 qualifiers with these basic types to get more types. There are 2 types of qualifiers- qualifier signed & unsigned Size qualifier short & lo - data types in C can be classit das follows: Type Storage size Value range Char |_| byte =128 10 127 unsigned char T byte Dw? Integrity [2 or 4 bytes 32,768 to 32,167 oF -2,147, 483,048 t 147,483,047 hnsigned imegrity [2 or 4 bytes or 0 10 4,294,967,295 \ Short | 2 bytes unsigned short [2 bytes I long | 4 bytes =2, 147,483,048 to 2, 147,483,604 | unsigned long | 4 bytes 0 to 4,.294,967,295 Type | Storage size Value range Precision float [4 bytes 1.2E-38 to 34E=38 6 decimal places double [8 bytes 2.3E-308 to 1.7E=308 15 decimal places long double [10 bytes aes 1TE+4932 19 decimal places Fopic: Components of C larguage, Standard /O in C, Fundamental data types, Variables and memory locations EMENTS OF © Every language has some basic elements & grammatical rules. Before starting with programming, we should be acquainted with the basic elements that build the language. Character Set Communicating with a computer involves speaking the language the computer understands. In ——~C. various characters have heen given to communicate. Character set in C consists of; Types Character Set [Lower ease fez JUpper case AZ [Digiss 9 Special Character [(@#S%°&* Vhite space [Tab or new lines or space Keywords Keywords ere the words whose meaning has already been explained to the C comp: "keywords cennot be used 2s variable names becuse i ng 10 a yew meaning to the keyword, which is not allowed by the computer. There are only 32 words available in C. Below figure gives a list of these keywords for your ready reference, KEYWorDS . auto do goto signed unsigned break = double if sizeof void case else int static volatile chat enum — tong struct while const extern register switch continue — float return typeodef default for short identifier In the programming language C, an identifier is a combination of alphanumeric characters, the first being a letter of the alphabet or an underline, und the remaining being any letter of the abet, any numeric digit, or ihe underiine, — Two rules must 6¢ kept in mind when naming identi 1. The case of aaphabetic: characte-s nificant, Using "INDEX" for a variable is no: the samé as using "index" and né.. icf 1 them is the same as using "InDeX" for a variable, All three refer to different ve 2. As C is defined, up t. ¢ ignificant by mos: compilers. 1f © compiler. jables. nificant characters ean be used and will be considered re than 32 are used, they will be ignored by the Constants A constant is an entity that doesn’t change whereas a variable is an entity that may change constants 1 be divided into two major categories: Primary Constants, Secondary Constants Constant Primary constant Secondary Constant Array Integer constant Pointer Real integer Structure Character constant Union Enum. Ete Rules for Constructing Integer Constants: * An integer constant must have at least one digit © [tmust not have a decimal «© Itcan be either positive or » * Inno sign precedes an integer cons med to be positive. © No commas or blanks are allowed within an integ * The allowable range for integer constants is -32768to 32767 Ex.: 426, +782.-8000. -7605 ant it is as: oF constant Rules for Constructing Real Constants: © Real constants are often called Floating Point constants, The real constants could be written in two forms—Fractional form and Exponential form. * A real constant must have at least one digit # It must have a decimal point # It could be either positive or negative * Default sign is positive * No commas or blanks are allowed within a real consta 48.5792 4325.34, 426.0, -32.76, - Rules for constructing real constants expressed in exponential form: © The mantissa part and the exponential part should be separated by a letter e. * The mantissa part may have a positive or negative sign * Default sign of mantissa part is positive. Lecture Notes| | Programming for Problem Solving (KCS-101/KCS-201) | |.K. Swarnakar@IT-GCET © The exponent must hi by ni ‘Xponent must have at least one digit, whiel Define + Which must be a positive oF negative integer * Range of real constants expressed in tial form is -3.4) 403: is essed in exponential form i 8 “3.4038 to 3.4e38, © EX. +3.2e-5. 4 1e8, -0.2¢+3 3.2e-5, Rules for Constructing A character constant Character Constants: is @ single alphabet, a single digit or a sin single inverted commas. special symbol enclosed wishin The maximum length ofa character constant can be | character Bs tMg, sae VARIABLES, Variables are na time, A data type that are used to store valugs. It can take different values but one at & s associated with each variable & it decides what values the variable ean take, Variable declaration requires that you inform C of the variable’s name and data type Syntax — data type variable name; Egcim page_no; char grade: float salary: long y; Declaring Variables: ‘There are two places where you can declare a variable: After the opening brace of a block of code (usually at the top of a function) Before a function name (such as before main() in the pro va am) Consider various examples: Initialization of Variables When a variable is declared, it contains undefined value commonly known as garbage value, Lf we want we can assign some initial value to the variables during the declaration itself, This called initialization of the variable. no= 10; expressions An expression consists of a combination of operators. ope! be , logical or relational. Tei nds, variables & function calls, An ‘are some expressioi atb~ arithmetic operation a>b- relational operation a b- logical operation fune (a,b) — function eall Statements Statements are the primary building blocks of a program. A program is as st 7 an RUNCHIATTON. A SATEMENU 1s @ comiplete instruction to the computer. In val d_a semicolon is needed to identity am is a series of statements a setticolon at the end. INPUT-OUTPUT IN C ‘am, This can be provides a set of built-in yen in When we are saying Input that means we feed some dans ins Pe the form of file or fram command Tine. C programming fanguags DS functions 1o read given input and feed it to the program as per rest When we are saying f et ea eae pate to display some data on sereen, printer or in any file. 2 guage provides a se! f built-i rn AG Same set of built-in functions to output the data on the Functions print) and. inf) are the most com: tions rit monly used to disphry e respectively. Let us consider an example > oT | #include //This is needed to run printil) function, int main() { printt"C Programming") 1 Output:C Programming Explanation: ‘displays the content inside quotation return 0: Every program starts from maing) function. printi() is a library function to display output whieh only works if #include int main() qint ¢ printit"Number="% return 0; OurputNumber=5 Input - Output of characters include int main() tehar varl: printii"Enter chara scanfi"%c".&varl); printf" You entered %c. return 0; tel var); Output-Enter character: g You entered g Ce Syotax eau ~> Synters cmrvr by au eur ur he Bee cod obo beg > Comput pr ds erg wut fellas abit x to lmprle aspect of tre ela, frat + mot : t $ ‘ angeeg® wl \ Conve tt imi fo enfrem He mK ee qe bgt | / 43 stake 2 mussig cut quotes 7 pesos out Bracke 7 Uy Supper cone cheater tun kepuseelt J GE ivshead : oh 4 2 Mini mut a Clon ot semicolon at fie endef 4 Bratt s veg deka 1 He we ovolt eal err “ a pawns Aorta cola. 2D ao ag" ot anustake. fat gtealt a 7 tone et ot a the of Aan bm ms unerpected belauicurn - ema Hab ferduce dee Topic: Arithmetic exp OPERATORS logical m Operators, operators, An operator is as} Module ~ 2: (Arie sions and precedence: Operators ional operators, mixed operands, type NS, assignment operator, operator precedence anipulations. C lan is rich in buil Mise Operators etic expressions & Conditional Branch Arithmetic operator: Assume variable A holds 10 and variable B holds 20 then} operators and provides the fol “DPES UT OPERATE Arithmetic Operators. Relational Operators. Logical Operators. Batwise Assignment Operators, Increment and decrement operators, bol that tells the compiler 1 perlorm specific mathematical or Conditional Operator Des ription Fxample two operands A> Buwillgnve ‘Subtracts second operand from the first Bwillgive-10 Multiplies both operands | | A* Bwill give 200 Divides nam, oF by de-numerator Modulus Operator and remainder oF alier an integer Division Increments operator increases inicyer value by one B A will Decrements operator decreases integer value by one » i ation ste WOper variable operat ators: \ holds 10 and variable B holds 20, then: or Description Example —T Cheeks ifthe values of two operands are equal or not, if yes then condition becomes true. (A == B) isnot truc. ! Checks if the values of two operands are equal or not. il values are not equal then condition becomes true (A! B) is true. ST Cheeks ithe value of left operand is greater than the value of right operand, if yes then condition becomes true (A > B) is not true. Checks if the value of leit operand is less than the value of right operand, if'yes then condition becomes tue (A = B)is true. IChecks if the value of left operand is greater than or equal to (A >= B) is not the value of right operand, if yes then condition becomes true true, | <= Checks if the value of lef operand is less than or equal to the | (A <= B) is Gue | value of right operand, if yes then condition becomes true, \ eal Operators: Assume variable A holds and variable B holds 0, then: Operator | Descrip! Example Called Logical AND operator. Ifboth the operands are &E nonzero, then condition becomes true. (A && Byis false Called Logical OR Operator, [any of the wo operands is non-zero, then condition becomes true. (A || B) is vue Called Logical NOT Operator. Use to reverses the | Late of its oper nd. If'a condition is true then Logical NOT. operator will make false. WA && Bris true | irks on bits and performs bit-by-bit operation. Th OR). ’ (XOR). << (left shifty and >~ (r operators can operate and double..Bit wise operators in C language are. & (bewice AND). 1 se AND). shift). The truth tables for &, Q p&q pig p’q ] 0 0 0 0 a | ) 1 0 ! 1 1 y 1 1 0 | 1 0 0 T T | able A holds 60 (00111100) and variable B holds 13 (00001101), then Operator Description | Example & | Binary AND Operator copies a bit to the result exists in both operands. \ (A & B) will give 12. which is 0000 1100 one operand but not both. \ [Binary OR Operator copies a bit fit exists in either (A] B) will give 61. and. | which is 0011 1101 | | | \ [ Zi Binary XOR Operator copies the bit if it is set in (A By will give 49. | which is 0011 0001 | ~ [Binary Ones Complement Operator is una} the effect of “flippi (A ) will give -61. which is 1100 0011 in 2's value is moved right by the number of bits specitied by the right operand. complement form. ==_| Binary Left Shift Operator. The left operands value Twill give 240 is moved left by the number of bits specified by the which is FEET 0000 right operand, >> Binary Right Shift Operator. The left operands A>>2willgive which is 0000 1111 orators ssignmen ys sues for the variables arc a ed using assignment operators, rene wing assignment operators supported by C language he gfe folowing aril ; : ‘operato Description Example | rt —fiple assignment operator, Assigns values rom right side CATR WIT operands to left side operand assign value of A+ B into ] AND assignment operator, Itadds right operand to the his left operand and assign the result tv left operand equivalent to C=C +A > Subtract AND assignment operator, It subtracts right Ais bperand fiom the left operand and assign the result to left equivalent to C=C Operand -A T=] Multiply AND assignment operator, It multiplies right C= Ais loperand with the left operand and assign the result t0 left equivalent to C=C Operand A = [Divide AND assignment operator, It divides le operand CHAS itls the right operand and assign the result fo left operand equivalent 0 C= C A T= pdulus AND assignment operator, It takes modulus using twvo operands and assign the result to left operand Tet shift AND assignment operator pe Right shift AND assignment operstor C >>= 2 is same as C=C>>2 Bitwise AND assignment operator C& 2 is same as C=C&2 ™ Diwise exclusive OR and assignment oper Dis same as C = biawise inclusive OR and assignment operator C |= 2 ts same : ant OPERATOR nent/Decreme! ; ik are cailled increment and decrement operators respectively. Both of these operators are neve! uscd on single operand, +f adds | to operand and ~ subtracts 1 1 operand ‘ dC ry operators, ik. tively. For example: J ee nd b=10 Leta rand a becomes 6 ‘a bee ‘a becomes 6 1. a becomes 5 When i is used as prefix(like: ++var), +-+var will increment the value of va on is used as postfix(like: var++), operator will return the value of operand first and then only increment it. This can be demonstrated by an examp! and then return it but, if relude int main() this statement displays 2 then, only c incremented by | to 3 /ithis statement increments I to ¢ then, only ¢ is displayed Print{%od"~=ey Return 0: Ourput:2 4 Conditional Operators (° Conditional operators are used in decision making in C programming, i.e. executes different statements condition whether itis either true or false.> Syntax of conditional operators; aitio ression expression l:expression? If the test condition is true (that is, iff its value is non-zero), expression! is returned and if false expression? is returned (x= 523:4) :Dthis statement will store 3 in y if x is greater than 5, otherwise it will store 4 in y y Mise Operators: There are few other operators supported by c language. Operator Description ple sizeoh) | It is a unary operator which is used in |sizcola), where ais integer, will finding the size of data type. constant, return 4 arrays, structure ete. & Returns the address ofa variable. | &az will give actual address of the variable WHT pointer to a variable : Pointer to a variable. 7 operators Precedence in C Gperator precedence determines the grouping of terms in an expression. This affects how an expression js evaluated. Certain operators have higher precedence than ‘others; for example, the multiplication operator has higher precedence than the addition operator. eae fas ae poceeampiex= 7 #3 * 2: here, x isassigned 13, not 20 because operato! + so it first gets multiplied with 3#2 and then adds into tors with the highest precedence appear at the top of the table. those with the lowest ape: * has higher precedence than ae Here, ope! ithe bottom. Within an expression, higher precedence operators will be evaluated first Category Operator Associativity Postfix Oe. == Left to right Unary (iype)® &sizeor Right to lett | > Multiplicative *7% Tote ren | 7 Additive - Left to right Shift Teli to ight Relational Tefitorght | | ead E Left to right t | Bitwise AND & Lettto right | Bitwise XOR Lette right Bitwise OR Lelitor Logical AND xx Telttonght | Togical OR Tel Conditional ” Right to lett 1 = Right w ett 4 Comma Let _ and else, Topic: Conditional Branchi Applying if and switch statements, nesting. use of break and Default with switch, If, ifelse, Case switeh statements CONTROL STATEMENTS, Control states be executed They siglements are class nts enable Ws to specify the order in which the various instructions in the program are to ‘efine how the control red To other parts of the program, Control Selection/tranching eect { ne | == Ce a) If statement Syntax: it{boolean_expression} 1 /* statement(s) will execute if the Boolean expression is true * If the Boolean expression evaluates to true then the block of code inside the if statement will be executed. If boolean expression evaluates to false then the first set of code alter the end of the if statement (after the closing curly brace) will be executed. C programming language assumes any non-zero and non-null values as true and if it is either zero or null th value Flow Diagra a it is assumed as false Se EE Nample: #include int main () { inta=10; iff a< 20) { Printita is less than 20\n" ); } Printit"value ofa is : %d\n", a); When the above code is compiled and executed, it produces following result a is less than 20; value ofa is: 10 (b) if-else statement Syntay: The syntax ofan if..clse statement in C programming language i if{boolean_expression) ement(s) will execute if the boolean expressivn is true "/ | /* statement(s) will execute if the boolean expression is false */ If the Boolean expression evaluates to true then the if block of code will be executed otherwise else block of code will be executed programming language assumes any non-zero and non-null Values as true and if it is either zero or null then it is assumed as false value. Flow Diagram: If condition true If condition is false Example: Hinchide main () 1 inta= 100; ifa<20) 1 Printi("a is less than 20\n" x» else { Printit"a is not less than 20\n" ); i Printil"value of a is Yod\n". a);} \ When the above code is compiled and executed, it produces following result a is not less than 20: Peo value ofa is: 100 Ise statement fatement is as follow (c) Nested if The syntax fora nested if's if boolean_expression 1) {Executes when the Boolean expression | is true */ if{boolean_expression 2) * Executes when the Boolean expression 2 is true * Example: #include main () {int a= 100; int b = 200; \ if a== 100) t ift 200) { printf("Value of a is 100 and b is 200\n" ); } printtt"Exact value ofa is : %din", a); print{("Exact value of b is : Yod\n", b ): return 0: When the above code is compiled and executed. it produces following result: Value of a is 100 and b is 200 Exact value of a is : 100 Exact, value of b is : 200 (d) A switch statement Allows a variable to be tested for equality against a list of values. Each value is called a case, and the variable being switched on is checked for each switch ease. Syntax. switeh(expression) {case constant-expression statement(s); break: * optional */ case constant-expression + statement(s); break; * optignal */ ‘* you can have any number of case statements */ default: Optional * statement(s): The following rules apply to a switeh statement * You can have any number of ease statements within a switch, Each case is followed by the value to be compared to and a colon A The constant-expression for a case must be the s me data type as the variable in the swviteh, and it must be at constant or a literal © When the sariable being switehed on is equal fo a case, the statements following that case will excette until a break statement is reached When a break statement is reached, the swviteh terminates, and the flow of control jumps to the nevt ling following the switeh statement «Not every case needs to contain a break, Hino break appears. the Mow of contro! will fall through fo subsequent cases until « break is reached 4 Aswitch statement ean have an optional default case, which must appear at the end of the savitch ‘The default case can be used for performing a task when none of the cases is true. No break is needed in the default case Flow mM: ° Example: main () 4 char case ‘Well done\n" ); ‘You passed\n" ); print{("Better try again\n" ); break: default print{("Invalid grade\n" J; Whe: the abs | prinui("Your grade is %e\n", grade ); de is compiled and executed, it produces following result Well don Your grade is B

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