What does the case structure test, in order to determine which set of statements to execute?

A case structure, or switch statement, is a control flow statement that allows a program to select a set of statements to execute depending on the value of a specific variable or expression. It is a more efficient way to handle multiple conditions in comparison to using nested if-else statements.

The case structure tests a specified variable or expression by comparing it to the values given in each case. When a match is found, the corresponding set of statements for that case is executed. If no matching case is found and a default case is provided, the statements under the default case are executed.

Suppose we have an integer variable called 'dayOfWeek' representing days of the week, with values 1 to 7. We can use a switch statement to execute specific actions based on the day of the week. ``` switch (dayOfWeek) { case 1: // Execute statements for Monday (e.g. print "Monday") break; case 2: // Execute statements for Tuesday (e.g. print "Tuesday") break; case 3: // Execute statements for Wednesday (e.g. print "Wednesday") break; // and so on for the rest of the week default: // Execute this when none of the above cases match (e.g. print "Invalid input") } ``` In the example above, the case structure tests the value of 'dayOfWeek'. When a match is found (e.g., dayOfWeek is 1), the statements for the matching case (in this example, print "Monday") are executed. If no matching case is found, the statements under the default case will be executed (in this example, print "Invalid input"). In conclusion, a case structure tests a specific variable or expression to determine which set of statements to execute. It does so by comparing the variable or expression with the values provided in each case, and executes the statements associated with the matching case.