CMSC131 REVIEW QUESTIONS WITH VERIFIED
ANSWERS
Why are there 8 different numeric types in java? - Answers - Because java is a
restrictive language: it requires that the bit count is noted and known. Different types
have different bit counts, so it shows the size.
How would you write an int and float constants? - Answers - int i= number;
float f= number;
How would declare a variable with initialization versus without? - Answers - with:
int i= 2;
without:
int i;
What is the order of precedence? - Answers - 1. parentheses/brackets
2. cast/new objects
3. multiplication/division
4. addition/subtraction
5. relational (instanceof)
6. equality
7. and (&&)
8. or (||)
9. assignment
How would you print "Hello World" onto one line? - Answers - System.out.print("Hello ");
System.out.print("World");
How would you print "Hello World" onto 2 separate lines? - Answers -
System.out.println("Hello");
System.out.println("World");
What is the difference between system.out.println(); and system.out.print(); - Answers -
println prints the messages on different lines while print prints the messages on the
same line
How can you convert an int to a char? - Answers - Declaration
1. set the char to a variable
2. set an int variable to that char variable
NumericValue
1. create an int variable that is the Character.getNumericValue(charVariable);
, String Value of
1. Create an int variable
2. assign it to Integer.parseint(String.valueOf(c));
How do you cast a float to an int? - Answers - Math.round
1. use Math.round();
Type Casting
1. int value= (int) 3.10f//
How do convert an int to a char? - Answers - Type Casting
int a=65;
char c=(char)a;
Character.forDigit()
int a=1;
char c= Character.forDigit(a);
What is a widening type conversion? - Answers - When you are casting a type object to
a greater primitive data type:
-byte to short, int, long, float, or double
-short to int, long, float, or double
-char to int, long, float, or double
-int to long, float, or double
-long to float or double
-float to double
What is a narrowing type conversion? - Answers - When you are going from a larger
primitive data type to a smaller, meaning you must cast the type/round it.
How would you declare a char variable equal to a? - Answers - char ch= 'a'; //needs
single quotes
How would you generate a random number? - Answers - Math.random(); //returns
double between 0.0 and 1.0
Random class:
Random rand= new Random ();
int r= rand.nextInt(100); //number 1 to 99
ANSWERS
Why are there 8 different numeric types in java? - Answers - Because java is a
restrictive language: it requires that the bit count is noted and known. Different types
have different bit counts, so it shows the size.
How would you write an int and float constants? - Answers - int i= number;
float f= number;
How would declare a variable with initialization versus without? - Answers - with:
int i= 2;
without:
int i;
What is the order of precedence? - Answers - 1. parentheses/brackets
2. cast/new objects
3. multiplication/division
4. addition/subtraction
5. relational (instanceof)
6. equality
7. and (&&)
8. or (||)
9. assignment
How would you print "Hello World" onto one line? - Answers - System.out.print("Hello ");
System.out.print("World");
How would you print "Hello World" onto 2 separate lines? - Answers -
System.out.println("Hello");
System.out.println("World");
What is the difference between system.out.println(); and system.out.print(); - Answers -
println prints the messages on different lines while print prints the messages on the
same line
How can you convert an int to a char? - Answers - Declaration
1. set the char to a variable
2. set an int variable to that char variable
NumericValue
1. create an int variable that is the Character.getNumericValue(charVariable);
, String Value of
1. Create an int variable
2. assign it to Integer.parseint(String.valueOf(c));
How do you cast a float to an int? - Answers - Math.round
1. use Math.round();
Type Casting
1. int value= (int) 3.10f//
How do convert an int to a char? - Answers - Type Casting
int a=65;
char c=(char)a;
Character.forDigit()
int a=1;
char c= Character.forDigit(a);
What is a widening type conversion? - Answers - When you are casting a type object to
a greater primitive data type:
-byte to short, int, long, float, or double
-short to int, long, float, or double
-char to int, long, float, or double
-int to long, float, or double
-long to float or double
-float to double
What is a narrowing type conversion? - Answers - When you are going from a larger
primitive data type to a smaller, meaning you must cast the type/round it.
How would you declare a char variable equal to a? - Answers - char ch= 'a'; //needs
single quotes
How would you generate a random number? - Answers - Math.random(); //returns
double between 0.0 and 1.0
Random class:
Random rand= new Random ();
int r= rand.nextInt(100); //number 1 to 99
