Java Control Structures and Sample Program

The if-else structure allows a program to execute different blocks of code depending on whether a specified condition is true or false.

Selection structures like if-else and switch let programs choose which code to execute based on different possible conditions.

In an if-else statement, the else block is executed only if the condition in the if block is false. Since the number 0 is less than or equal to 0, it falls under the condition for the else block and outputs "0 is a negative value".

The code snippet does not have an else block to handle the case when the number is 5. Therefore, no output will be displayed because the if condition is not met.

The else if structure allows a programmer to check for additional conditions if the preceding if or else if condition fails. This helps to create more complex decision-making logic within the program.

The switch structure offers a way to execute different code blocks based on specific values or cases. It's a more efficient way to handle multiple conditions than using a series of if-else statements.

In a series of else if statements, if no preceding condition is true, the final else block will be executed as the default case.

The last else statement in a chain of else if statements acts as a default condition, ensuring that some code will execute even if none of the preceding conditions are met.

Based on the code provided, an exam mark of 75 would fall within the range of 70-80, resulting in a grade of 'A'.

Logical operators such as && (AND), || (OR), and ! (NOT) allow programmers to combine multiple conditions within a single conditional statement. This makes the code more flexible and allows for more complex decision-making.

In Java, && (AND) operator requires both conditions to be true for the entire expression to be true. Since one condition is false, the entire expression evaluates to false.

In Java, the || (OR) operator requires at least one of the conditions to be true for the entire expression to be true. Since both conditions are false, the entire expression evaluates to false and the message is not printed.

Operands are the values or expressions that logical operators work on. In the case of Java's logical operators, operands are expressions that evaluate to either true or false.

When Java encounters the && (AND) or || (OR) operator, it first evaluates the left-hand side of the expression. This is because the left-hand side may or may not be sufficient to determine the overall result of the expression. In that case, the right-hand side may not need to be evaluated.

Since num1 is less than 0, the first condition evaluates to false (num1 > 0) and the entire expression becomes false because of the && operator. The second condition (num2 < 0) will not be evaluated since the overall result is already determined by the false first condition.

Logical operators are primarily used to combine multiple conditions in conditional statements, allowing for more complex and nuanced decision-making in Java programs.