Introduction to Programming

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Introduction to Programming

• Lecture 5

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In the Previous Lecture

• Basic structure of C program
• Variables and Data types
• Operators
• cout and cin for output and input
• Braces

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• Decision

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If Statement

• If condition is true
• statements
• If Alis height is greater then 6 feet
• Then
• Ali can become a member of the Basket Ball team

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If Statement in C

• If (condition)
• statement

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If Statement in C

• If ( condition )
• statement1
• statement2

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If statement in C

• if (age1 gt age2)
• coutltltStudent 1 is older than student 2

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Relational Operators

• lt less than
• lt less than or equal to
• equal to
• gt greater than or equal to
• gt greater than
• ! not equal to

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Relational Operators

• a ! b
• X 0
• X 0

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Example

• include ltiostream.hgt
• main ( )
• int AmirAge, AmaraAge
• AmirAge 0
• AmaraAge 0
• coutltltPlease enter Amirs age
• cin gtgt AmirAge
• coutltltPlease enter Amaras age
• cin gtgt AmaraAge
• if AmirAge gt AmaraAge)
• cout ltlt \nltlt Amirs age is greater then
  Amaras age

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Flow Chart Symbols
Start or stop
Process
Flow line
Continuation mark
Decision
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Flow Chart for if statement
Entry point for IF block
IF
Condition
Then
Process
Exit point for IF block
Note indentation from left to right
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Example

• If the student age is greater than 18 or his
  height is greater than five feet then put him on
  the foot balll team
• Else
• Put him on the chess team

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Logical Operators

• AND
• OR

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Logical Operators

• If a is greater than b
• AND c is greater than d

In C if(a gt b cgt d) if(age gt 18 height gt 5)
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if-else

• if (condition)
• statement
• -
• -
• else
• statement
• -
• -

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if-else
Entry point for IF-Else block
IF
Condition
Then
Process 1
Else
Process 2
Exit point for IF block
Note indentation from left to right
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Example
Code if (AmirAge gt AmaraAge) coutltlt
Amir is older than Amara if (AmirAge lt
AmaraAge) coutltlt Amir is younger than
Amara
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Example

• Code
• if AmirAge gt AmaraAge)
• coutltlt Amir is older than Amara
• else
• coutltltAmir is younger than Amara

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• Make a small flow chart of this
• program and see the one to one
• correspondence of the chart
• and the code

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Example

• Code
• if AmirAge gt AmaraAge)
• coutltlt Amir is older than Amara
• else
• coutltltAmir is younger than or of the same
  age as Amara

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Example

• If (AmirAge ! AmaraAge)
• cout ltlt Amir and Amaras Ages are not equal

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Unary Not operator !

• !true false
• !false true

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• If (!(AmirAge gt AmaraAge))
• ?

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Example

• if ((interMarks gt 45) (testMarks gt
  passMarks))
• cout ltlt Welcome to Virtual University

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Example

• If(!((interMarks gt 45) (testMarks gt
  passMarks)))
• ?

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Nested if

• If (age gt 18)
• If(height gt 5)
• Make a flowchart of this nested if structure

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In Todays Lecture

• Decision
• If
• Else
• Flowcharts
• Nested if