if else

Question 1

Correct the following:
if ( grade >= 60 ) ;

Answer 1

logic error, in if-else statement you must not include a semicolon after “if” nor after “else”.

Question 2

What makes a one way selection in an if-else statement/program?

Answer 2

it includes only the if statement without the else
ex:
if (grade >= 90 )
System.out.println( “pass”) ;

System.out.println(“end.”) ;

Question 3

if you want to add two messages to be printed after the if statement what do you?

Answer 3

you put them in a block via ( { ), ex:
if (grade >= 90 ){
System.out.println( “pass”) ;
System.out.println(“congrats.”) ;
}
System.out.println(“done.”) ;

Question 4

Correct the following:
if ( grade >= 60) ;
System.out.println(“bark bark.”) ;
else
System.out.println(“meow.”) ;

Answer 4

compile error, when we put a semicolon after an if statement and there is an else statement after it then it is a compile error.

Question 5

T/F: writing [ default : ] in a switch code is optional.

Answer 5

TRUE

Question 6

T/F: you can use a switch code to write an if-else code.

Answer 6

true

Question 7

How to write a switch code

Answer 7

switch ( — )
{
case —— :
System.out.println(“”) ;
break ;
}

Question 8

You are not allowed to use a switch code on ________ or _________ variable.

Answer 8

boolean, double

Question 9

T/F: You are allowed to use int, char, and string variable for a switch code.

Answer 9

true

Question 10

T/F: you have to write a break for a switch code.

Answer 10

false, you dont have to.

Question 11

T/F: Order doesn’t matter in a switch code as long as they’re numbered.

Answer 11

false, order of the cases does matter, and the numbering doesn’t.

Question 12

What is th purpose of Math.random() ?

Answer 12

it gives you a random number within the range of (0 - one digit less than the number you multiplied it by)

Question 13

guess the range:
Math.random() * 100

Answer 13

0 - 99

Question 14

correct the following:
int num1 = Math.random() * 100 ;

Answer 14

int num1 = (int) (Math.random() * 100 ) ;

we must always cast the math random outcome

Question 15

when you have && you skip the second statement if ……

Answer 15

the first is false.

Question 16

T/F: when you have &
you skip the first statement.

Answer 16

false, you don’t skip the first or the second statement.

Question 17

rewrite this code using the condition operator:
If( result == answer )
System.out.println( “ Correct “ ) ;
else
System.out.println( “ Error “ ) ;

Answer 17

System.out.println( result == answer ? “Correct” : “Error” ) ;

Question 18

in the condition operator, the semicolon is the equivalent of an __________ in an if-else statement.

Answer 18

else statement

Question 19

write the code for a char type variable input

Answer 19

char ch = input.next().charAt(0) ;

Question 20

print the outcome:
int x=1; int y=2;
if ((x=0)==0)
System.out.println(“111”);
else if (x==1)
System.out.println(“222”);
else
System.out.println(“333”);

Answer 20

111