The do-while StatementFEROL JOHN NOHAY

do-while Statement• In this statement, the logical expression is tested in the end of each iteration instead of at the beginning.

• Post-Test loop – logical expression in each iteration is tested after the body of the loop.

• The do-while statement has 5 parts:• The reserved word (do)

• The statement on the body of loop

• The reserved word (while)

• The logical expression in the parenthesis

• Semicolon (required)

do-while Statement• Event-Controlled Loop

• At least One Iteration

The do-while loop is the recommended solution when a problem that the body of the loop be executed at least once.

do-while StatementExample: We want to write a program that extracts and prints the left-most digit of any nonnegative integer.

do-while Statement• Data Validation – should be included in a program whenever a user enters a data that must match a set of criteria.

• It ensures that the user have entered all of the required data in the proper format.

do-while StatementExample: when we change a numeric score to a grade, test scores are usually in the range of 0 and 100

Result: if value is valid

Result: if value is invalid.

More about Loops

Comparison of Three LoopsFeature While loop For loop Do-while loop

Test type Pre-test Pre-test Post-test

Primary Design

event-controlled counter-controlled event-controlled

Minimum Iterations

0 0 1

Number of test

n+1 n+1 n

Nested loop• Nested loop – a loop inside another loop. The inside loop does not have to be of the same type as the outside loop.

• Most used nested loop: for loop

• for loop (outer) : rows

• for loop (inner) : columns

Nested loopExample 1:

Nested LoopExample 2:

Other Related Statements

The return Statement• return statement – terminates the current function immediately and returns control to the function caller

• return statement in a loop – causes the loop to terminate and the function in which the loop is iterating to be terminated.

•Example: Determine if a number is composite or prime number. • Step 1: If the number is 1, the number is not a prime number.

• Step 2: If the number is divisible by any number less than itself, it is composite

The return StatementExample:

Result 1:

Result 2:

Result 3

The break Statement• Break statement – can be used in a loop or a switch statement.

- to come out a loop prematurely when we need to.

The continue Statement• The continue Statement – skips the remaining statements in the body of that statement and proceeds with the next iteration of the loop.

Try this!!• Using nested loop: for-loop

• Create a multiplication table wherein the user must input the size from 2 to 10.

• NOTE: use manipulator: setw(4) to set the field width.

• Hint: use do-while loop for Data Validation wherein it will ask the user if he/she has input the size greater than 10 or less than 2.

Try this!!Sample output:

NOTE: the first 2 lines accepts input (cin) from the user