We have already seen in Unit 5 that the break statement allows us to exit a switch statement. In general, break allows us to exit prematurely from a switch, while, for, or do statement.
Example: Loop to calculate the square root of 10 reals read from input. We want to interrupt the loop as soon as the user inputs a negative value.
double a; for (int i = 0; i < 10; i++) { a = Double.parseDouble( JOptionPane.showInputDialog("Input a nonnegative real")); if (a >= 0) System.out.println(Math.sqrt(a)); else { System.out.println("Error"); break; } }
Note: In the case of nested loops or of switch statements nested within a loop, the execution of a break causes the exit from a single level of nesting only.