Conditional Statements in with C++
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Check Bytes in Memory – Real Numbers
• get information for following data types:
– Float
– double
– long double
• Use ( cout << sizeof(float); ) operator to get
this information, Example:…
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If Statement in C/C++
• Supports the use of a decision structure
• Allows statements to be conditionally executed or skipped
over
• Models the way we mentally evaluate situations
“If it is cold outside,
wear a coat and wear a hat.”
The block inside the braces is called the body of the if statement. If there is only 1 statement in the body, the { }
may be omitted.
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If Statement in C++
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If Statement (Example)
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If condition (Example using multiple statements )
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If Statement (Flag)
• A variable that signals a condition
• Usually implemented as a bool
• Meaning:
– true: the condition exists
– false: the condition does not exist
• The flag value can be both set and tested with
if statements
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If Statement (Example using Flag)
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Don’t Confuse == With =
• Not to confuse the equality operator (==) with the assignment(=)
• Example: operator (=), as in the following statement:
if (x = 2)
cout << "It is True!";
The statement above does not determine whether x is equal to 2, it assigns x
the value 2.
Furthermore, the cout statement will always be executed because the
expression x = 2 is always true.
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Important points about if
• if is a keyword. It must be lowercase
• (condition) must be in ( )
• Do not place ; after (condition)
• Don't forget the { } around a multi-statement body
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if/else Statement
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The if/else Statement
Allows a choice between statements depending on whether (condition) is true or false
true false
condition
statement set 1 statement
set 2
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if/else (Example)
if/else (Example with multiple statements)
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The else...if Construction
Chain of if statements that test in order until one is found to be true
“If it is raining, take an umbrella,
OR OR
else, if it is windy, take a hat,
else, if it is sunny, take sunglasses.”
else, you are good to go as is
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The else...if Example
if (marks>=80)
{
cout<<“\n You got A grade”;
cout<<“\n You won scholarship too”;
}
else if (marks>=70)
cout<<“\n You got B grade”;
else if (marks>=60)
cout<<“\n You got C grade”;
else if (marks>=50)
cout<<“\n You got D grade”;
else
cout<<“\n You are fail”;
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Practice Example
Write a program to calculate tax collection according to the
following formula:
– 5% Tax, if salary is above 50000
– 3% Tax , if salary is between 30000 and 50000
– 2% Tax, is salary is between less than 30000
In the end the program should print the calculated tax.
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Practice Tasks
• Write a program in C++ to find the Size of fundamental data types.
• Write a program in C++ to take two numbers as input and swap
them. Print before the swap and after the swap.
• Write an if statement that performs the following logic: if the
variable x is equal to 20, then assign 0 to the variable y.
• Write an if statement that performs the following logic: if the
variable price is greater than 500, then assign 0.2 to the variable
discountRate.
• Write an if statement that multiplies payRate by 1.5 if hours are
greater than 40.
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