morexperts.blogg.se - Why are there only 12 notes

In the case of the while loop shown above, it is not only empty but also infinite.

Printf( "i = %d\n", i++ ) // Again, this line is AFTER the loop. While( i < 5 ) // Error - empty loop on this line Printf( "i = %d\n", i ) // This line is AFTER the loop, not inside it.

A common error is to place an extra semi-colon at the end of the while or for statement, producing an empty loop body between the closing parenthesis and the semi-colon, such as:įor( i = 0 i < 5 i++ ) // Error on this line causes empty loop.

Printf( "I'm sorry, but %d is not a valid month.\nPlease try again.\n", month )

About the only place this is ever used is in for loops, to either provide multiple initializations or to allow for multiple incrementations.

C has a comma operator, that basically combines two statements so that they can be considered as a single statement.

Under "C compiler", add the line: -std=c99 ) You will also see occasions where the loop variable is declared as part of the for loop, ( in C99 ), in which case the variable exists only within the body of the loop, and is no longer valid when the loop completes:įor( int i = 0 i Project Options from the menu, and then selecting the Parameters tab.

In the example above, the variable i is declared before the loop, and continues to exist after the loop has completed.However it can be any legal C/C++ statement, such as "N += 3" or "counter = base + delta". The third part of the loop is labeled "incrementation", because it usually takes the form of "i++" or something similar.

for-loops are counter-controlled, meaning that they are normally used whenever the number of iterations is known in advance.Note that once you enter the loop, the operation is identical from that point forward: The following diagram shows the difference between while and do-while loops.Note that the above example could be improved by reporting to the user what the problem is if month is not in the range 1 to 12, and that it could also be done using a while loop if month were initialized to a value that ensures entering the loop.Where the body can be either a single statement or a block of statements within. While loops check for the stopping condition first, and may not execute the body of the loop at all if the condition is initially false.Both while and do-while loops alternate between performing actions and testing for the stopping condition.Both while loops and do-while loops ( see below ) are condition-controlled, meaning that they continue to loop until some condition is met.while Loops ( Condition-Controlled Loops ) In this section we will learn how to make computer repeat actions either a specified number of times or until some stopping condition is met. C Programming Course Notes - Looping ConstructsĬomputers are very good at performing repetitive tasks very quickly.