All Flashcards
What is an 'int'?
A primitive data type that stores whole numbers.
What is a 'double'?
A primitive data type that stores decimal numbers with high precision.
What is a 'boolean'?
A primitive data type that stores a truth value: either 'true' or 'false'.
What is a 'variable'?
A named storage location in memory that holds a value.
What is 'scope' in Java?
The region of the program where a variable is accessible.
What is 'initialization'?
Giving a variable its first value.
What is 'Integer Overflow'?
When an integer exceeds its maximum or minimum allowed value, wrapping around to the other end.
What does 'strongly typed' mean?
Once a variable has a data type, it cannot be changed to a different data type.
What is 'public' access modifier?
Accessible everywhere.
What is 'private' access modifier?
Accessible only within the class.
What are the differences between 'int' and 'double'?
int: Stores whole numbers | double: Stores decimal numbers with higher precision.
What are the differences between 'public' and 'private' access modifiers?
Public: Accessible everywhere. | Private: Accessible only within the class.
Identify the error in the following code:
int x = 3.14;
Cannot assign a 'double' value (3.14) to an 'int' variable.
Identify the error in the following code:
boolean flag = 1;
Cannot assign an integer value (1) to a 'boolean' variable. 'boolean' can only be 'true' or 'false'.
Identify the error in the following code:
double result = 10 / 3;
Integer division is performed (10/3 = 3), then the result is converted to a double (3.0). To get a double result, one of the operands must be a double (e.g., 10.0 / 3).
What does the following code output?
int max = Integer.MAX_VALUE; System.out.println(max + 1);
Integer.MIN_VALUE (due to integer overflow)
Identify the error in the following code:
private int 2variable = 10;
Variable names cannot start with a number.
Identify the error in the following code:
int public = 5;
'public' is a reserved keyword and cannot be used as a variable name.
What does the following code output?
double num = 5.0 / 2; System.out.println(num);
2.5
What does the following code output?
boolean isTrue = (5 > 3); System.out.println(isTrue);
true
Identify the error in the following code:
Int age = 20;
Java is case-sensitive. 'Int' should be 'int'.
What does the following code output?
int a = 5; int b = a + 2; System.out.println(b);
7