All Flashcards
What are the steps to execute an 'if' statement?
- Evaluate the condition. 2. If true, execute the code block. 3. If false, skip the code block.
What are the steps to execute a 'for' loop?
- Initialize the loop variable. 2. Check the condition. 3. If true, execute the loop body. 4. Increment/decrement the loop variable. 5. Repeat steps 2-4 until the condition is false.
What are the steps to execute a 'while' loop?
- Check the condition. 2. If true, execute the loop body. 3. Update the loop variable (if necessary). 4. Repeat steps 1-3 until the condition is false.
What are the steps to create an object from a class?
- Declare a variable of the class type. 2. Use the 'new' keyword followed by the class name and parentheses. 3. Optionally, initialize the object's fields.
What are the differences between 'for' and 'while' loops?
For: Used when the number of iterations is known. While: Used when the number of iterations is unknown, and depends on a condition.
What are the differences between == and .equals() when comparing strings?
==: Compares object references (memory locations). .equals(): Compares the content of the strings.
What are the differences between inheritance and polymorphism?
Inheritance: Allows code reuse and creates an 'is-a' relationship. Polymorphism: Allows objects of different classes to be treated as objects of a common type.
What does the following code output?
java
int x = 10;
if (x > 5) {
x = x * 2;
}
System.out.println(x);
20
What does the following code output?
java
int i = 0;
while (i < 4) {
System.out.print(i + " ");
i++;
}
0 1 2 3
What does the following code output?
java
String str = "Hello";
System.out.println(str.substring(1, 4));
ell
What does the following code output?
java
int[] arr = {5, 10, 15};
System.out.println(arr[1]);
10
What does the following code output?
java
String s1 = "Java";
String s2 = "Java";
System.out.println(s1.equals(s2));
true
What does the following code output?
java
int sum = 0;
for (int i = 1; i <= 3; i++) {
sum += i;
}
System.out.println(sum);
6
What does the following code output?
java
String str = "Computer";
System.out.println(str.length());
8
Identify the error in the following code:
java
int[] arr = new int[3];
System.out.println(arr[3]);
ArrayIndexOutOfBoundsException: Index 3 is out of bounds for an array of length 3.
What does the following code output?
java
int x = 3;
if (x % 2 != 0) {
System.out.println("Odd");
} else {
System.out.println("Even");
}
Odd
What does the following code output?
java
String str = "Hello World";
System.out.println(str.indexOf("World"));
6