TA ZC142-L4

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TA ZC142 Computer Programming

Lecture 3

Date: 16/01/2013

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Last Lecture

C Programming Basics

Arithmetic, Logical and Relational

Operators Precedence and Associativity

Flow Charts and Algorithms

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Todays Lecture

Flow Charts and Algorithms

Programming Examples

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Type Conversion

Implicit Type Conversion

Explicit Type Conversion

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Implicit Type Conversion

C automatically converts any

intermediate values to the proper data

type Lower type is automatically converted to

the higher type before operation

proceeds

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Relational OperatorsOperator Meaning

< Is less than

Is greater than

>= Is greater than or equal to

== Is equal to

!= Is not equal to

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Examples:

5 = 0 FALSE

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Logical Operators

Operator Meaning

&& Logical AND

|| Logical OR

! Logical NOT

Q. Are !(a>b) and a

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Increment and Decrement

Operators++ Adds one to the operand-- Subtracts one from the operand

Both are unary operators

++i is equivalent to: i = i+1

--i is equivalent to: i = i-1

Is ++i and i++ are same??

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Postfix and Prefix Examples

j =10;

i =j++;

What is the values of i and j?

j =10; i=--j;

What is the values of i and j?

Output

i = 10 j = 11

Output

i = 9 j = 9

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Conditional Operator

Also called Ternary operator

Syntax

Variable = expression1 ? expression2

: expression3

Example:

a=5;b=10;

x =(a>b) ? a : b;

What will be the value of x??

Output

X = 10

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Bitwise Operators

Manipulation of data at bit level

Not be applied to float or double values

Operator Meaning

& Bitwise AND

| Bitwise OR

^ Bitwise exclusive OR

> Shift right

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Operators Associativity Rank

(),[] L to R 1

+, -, ++, --, !, ~, *, &, sizeof,

(type)

R to L 2

*, /, % L to R 3

Binary plus(+) and Binary minus (-) L to R 4

L to R 5

= L to R 6

==, != L to R 7

& L to R 8

^ L to R 9

| L to R 10

&& L to R 11

|| L to R 12

?: R to L 13

=, *=, /=, %=, +=, -=, &=, ^= R to L 14

, L to R 15

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Algorithms An Algorithm is just a detailed sequence of simple steps

that are needed to solve a problem

Flow Charts Flow Charts are maps or graphical representations of a

process.

Steps in a process are shown with symbolic shapes, and

the flow of the process is indicated with arrowsconnecting the symbols

ALGORITHMS AND FLOW CHARTS

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Symbols in Flowchart

START , END

INPUT

PROCESS INPUT DATA

DECISION

CONNECTOR

CONNECTOR

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Example Flow Chart

Marks = 50

Avg = 45

Marks > avg

END

START

YES

NO

Flow chart to find

whether the the marks ofa student is above avg or

below avg

Print below Avg

Print above Avg

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Draw a flow chart for calculating the gross

salary of a employee if his basic salary is

input through the keyboard. if basic salary is

less than Rs.1500 then HRA = Rs. 500 and

DA = 90% of basic. If salary is equal or

greater than 1500 then HRA = 10% and DA

= 95% of basic salary.

Example on flowchart

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START

INPUT bs

is

bs < 1500

Hra = 500

Da = bs * 90/100

Hra = bs * 10/100

Da = bs * 95/100

Gs = bs + hra + da

PRINT

GSSTOP

NOYES

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Control Structure

Sequential Control Structure

Its a sequential flow of execution of instructions.

Selection Control Structure

This control structure chooses among alternative

program statements.Repetition Control Structure

This control structure repeats a group of program

statements till it satisfies some condition.

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if Statement

Selection Control Structure

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If Statement

if (condition)

{

statement-block; }

next-statement;

condition

Statement -block

T

F

Condition is a C expression, which evaluates to

TRUE (non-zero) or FALSE (zero).

Statement-Blockcan be a single statement

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Example If Statements

if (x

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More If Examples

if (age >= 0 && age

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If - else Statement

if (condition)

true block statement(s);

else

false block statement(s);

condition

True Block

statement

False Block

statement

T F

elseallows choice between two mutuallyexclusive actions without re-testing condition.

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If else Statement example

if (i>j) k = i++ + --j;

else

k = ++i + j--;if (i>j && j>k)

{ i++;

j++;

}

else{ k++;

j--;

}

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Chaining ifs and elses

if(condition 1)

statement-1;else if(condition 2)

statement-2;

else if(condition 3)statement-3;

else if(condition 4)

statement-4;else

default-statement;

next_statement;

Example

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Example

if(month == 4 || month == 6 || month == 9 || month == 11)

printf(Month has 30 days.\n);

else if(month == 1 || month == 3 ||month == 5 || month == 7 ||

month == 8 || month == 10 ||

month == 12)

printf(Month has 31 days.\n);

else if(month == 2)

printf(Month has 28 or 29 days.\n);

else

printf(Dont know that month.\n);

Program using if else ladder

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Program using if-else ladder

/* Checking a character whether it is capital letter or smallletter or special symbol*/

#include

int main(){

char ch;

printf("Enter a char:");

scanf("%c",&ch);if(ch>='A' && ch='a' && ch='0' && ch

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Nesting of

ifelse statements

if (condition 1)

{

if (condition 2)

{statement(s) 1;

}

else

{statement(s) 2;

}

}

else

{

statement(s) 3;

}

next_statement;

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Nested if examples

if (x == 3)if (y != 6) {z = z + 1;w = w + 2;

}

if ((x == 3) && (y != 6)) {

z = z + 1;

w = w + 2;

}

is the same as...

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Matching else with If

else is always associated with closestunassociated if.

if (x != 10)

if (y > 3)

z = z / 2;

else

z = z * 2;

if (x != 10) {

if (y > 3)z = z / 2;

else

z = z * 2;

}

is the same as...

if (x != 10) {

if (y > 3)z = z / 2;

}

else

z = z * 2;

is NOT the same as...

int main() {

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Example: nesting of if-elseprogram to find largest of

the three numbers

int main() {float a, b, c;

printf(Enter three values\n);

scanf(%f %f %f,&a, &b, &c);

printf(Largest value is);if(a>b)

{ if(a>c)

printf(%f,a);

else

printf(%f,c);

}

else

{ if(c>b)

printf(%f,c);else

printf(%f,b);

}

return 0;

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Exercise: on if-else

1. Write a program to determine whether a number isodd or even and print the appropriate message.

2. Write a program to find the smallest of the threenumbers.

3. Write a program to determine whether the inputtedyear is a leap year or not.

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4. Write a program that takes the x-ycoordinates of a point in the Cartesian

plane and prints e message telling eitheran axis on which the point lies or the

quadrant in which it is found.

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1. Write a program to determine whether a number is

odd or even and print the appropriate message.

2. Write a program to find the smallest of the threenumbers.

3. Write a program to determine whether the inputtedyear is a leap year or not.

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Write a program to reverse a three digit decimalnumber and determine whether the two numbers

are equal or not.

Write a program to add the digits of a number. Let

the number 4 digit only.

Write a program to convert a decimal number

ranging from 1 to 7 into binary.

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Write a program to calculate area of acircular ring.

Write a program that takes the x-ycoordinates of a point in the Cartesianplane and prints a message telling eitheran axis on which the point lies or thequadrant in which it is found.

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Write a program to implement the followingdecision table to characterize an earth quakebased on its Richter scale number.

Richter Scale Number(n)

Characterization

n < 5.0 Little or damage

5.0

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Any Doubts or Questions?

TA ZC142-L4

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