Lecture 4 selection statements

Chapter 4: Selection Statements chauvtn@hcmut.edu.vn... References Deitel and Harvey Deitel, Prentice Hall, 2012... Introduction  ended with a semicolon ;  stretched on multiple lines

Chapter 4: Selection Statements

chauvtn@hcmut.edu.vn)

References

Deitel and Harvey Deitel, Prentice Hall, 2012

– Brian W Kernighan and Dennis M Ritchie, Prentice Hall, 1988

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Introduction

 ended with a semicolon (;)

 stretched on multiple lines with a backslash \ at the end

 able to be grouped in the brackets {}

 not consider spaces

 specified by {} with no semicolon after the right brace

 contains as many statements as required

 is a compound statement, syntactically equivalent to a single statement

double minNumber = positiveNumber[0];

iteration = iteration + 1;

} } }

Block Single statement

double minNumber = positiveNumber[0];

iteration = iteration + 1;

} } }

Control Statements for Selection

Print “Passed” if grade >= 5.0

Otherwise, print “Failed”

if else statements

Which one do you prefer: conditional expressions or if else statements?

Nested if /if else statements

Nested if /if else statements

Nested if /if else statements

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Nested if /if else statements

Nested if /if else statements

switch (<expression>) {

case <case 1>: <Statements 1>; break;

case <case 2>: <Statements 2>; break;

of a number of constant

integer values, and branches accordingly

switch case statements

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switch (<expression>) {

case <case 1>: <Statements 1>; break;

case <case 2>: <Statements 2>; break;

…

case <case N>: <Statements N>; break;

[default: <Default>]

}

if (<expression> == <case 1>) <Statements 1>

else if (<expression> == <case 2>) <Statements 2>

switch case statements

enumerated data, characters

of the aforementioned types

through to the next unless an explicit action is

taken to escape

 break (return) statement

true (0) true (0) false (0) false (0) false (0)

switch (<expression>) {

case <case 1>: <Statements 1>

case <case 2>: <Statements 2>

switch case statements

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switch (<expression>) {

case <case 1>: <Statements 1>

case <case 2>: <Statements 2>

true (0) true (0) false (0) false (0) false (0)

switch case statement with “fall-through” property

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Put them all together

week Input a day in a week and output its corresponding activities

 int strcmp(const char *str1, const char *str2)

 < 0 if str1 < str2 (less than)

 > 0 if str1 > str2 (greater than)

 = 0 if str1 = str2 (equal)

 char *strcpy(char *destination, const char *source)

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Add more codes to make such an input valid (?!)

according to a “TRUE” ( 0) value of a

condition (expression)

in programming

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Chapter 4: Selection Statements