Example - 1

In the following code the method processMessagesFromServer attempts to establish a connection to a server and read and process messages from the server. The method uses a do/while loop to continue trying to establish the connection to the server when an attempt fails.

// // create socket to connect to server// 

// // establish connection to server// 
// // if connected then read and process messages from server// 

// // read and process messages// 
...
connected = connect(servsock, (struct sockaddr *)&servaddr, sizeof(servaddr));if (connected > -1) {}
// // keep trying to establish connection to the server// 
// // close socket and return success or failure// 
...int servsock;int connected;struct sockaddr_in servaddr;servsock = socket( AF_INET, SOCK_STREAM, 0);memset( &servaddr, 0, sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_port = htons(port);servaddr.sin_addr.s_addr = inet_addr(hostaddr);do {} while (connected < 0);...int processMessagesFromServer(char *hostaddr, int port) {}

However, this will create an infinite loop if the server does not respond. This infinite loop will consume system resources and can be used to create a denial of service attack. To resolve this a counter should be used to limit the number of attempts to establish a connection to the server, as in the following code.

// // initialize number of attempts counter// 

// // establish connection to server// 
// // increment counter// 
// // if connected then read and process messages from server// 

// // read and process messages// 
...
connected = connect(servsock, (struct sockaddr *)&servaddr, sizeof(servaddr));count++;if (connected > -1) {}
// // keep trying to establish connection to the server// 
// // up to a maximum number of attempts// 
// // close socket and return success or failure// 
...int count = 0;do {} while (connected < 0 && count < MAX_ATTEMPTS);...int processMessagesFromServer(char *hostaddr, int port) {}

Example - 2

For this example the method isReorderNeeded as part of a bookstore application that determines if a particular book needs to be reordered based on the current inventory count and the rate at which the book is being sold.

// // get inventory count for book// 
// // find number of days until inventory count reaches minimum// 

inventoryCount = inventoryCount - rateSold;days++;
// // if number of days within reorder timeframe// 
// // set reorder return boolean to true// 
isReorder = true;
boolean isReorder = false;int minimumCount = 10;int days = 0;int inventoryCount = inventory.getIventoryCount(bookISBN);while (inventoryCount > minimumCount) {}if (days > 0 && days < 5) {}return isReorder;public boolean isReorderNeeded(String bookISBN, int rateSold) {}

However, the while loop will become an infinite loop if the rateSold input parameter has a value of zero since the inventoryCount will never fall below the minimumCount. In this case the input parameter should be validated to ensure that a value of zero does not cause an infinite loop,as in the following code.

// // validate rateSold variable// 
return isReorder;
...if (rateSold < 1) {}...public boolean isReorderNeeded(String bookISBN, int rateSold) {}