Let's talk about not using break in PHP switch statement

It is very common to use switch statements to select multiple branches in PHP. Usually, a break statement is used to exit the switch statement after each branch. However, there are situations where we do not want to use the break statement. This article will introduce the situation of not using break in the PHP switch statement.

Why not use break

In most cases, when we use the switch statement, we will use the break statement to terminate the execution of the current branch. This is because if we do not use break statement, the program will continue to execute the subsequent branch. However, in some cases, we may need to let the program continue executing subsequent branches, in which case we do not need to use the break statement.

For example, we need to determine the user's VIP level. If it is VIP1, we need to provide special services to the user and send a message to the user. If it is VIP2, we only need to send a message to the user. If it is an ordinary user , then do nothing. This can be achieved using the following code:

$vip_level = 1;
switch($vip_level){
    case 1:
        give_special_service();
    case 2:
        send_message();
        break;
    default:
        break;
}

In the above code, when the user's VIP level is 1, the give_special_service() function is called, and the program will continue to execute the following branches, and then call the send_message() function . However, when the user's VIP level is 2, the send_message() function will be the first to be called, but the give_special_service() function will not be called.

Another example is: Suppose we have an order processing system. We need to determine the status of the order. If the order has been completed, we need to send an email to notify the user and record the order information. If the order has been cancelled, we need Record the order information. If the order status is other status, we do nothing. This can be achieved using the following code:

$order_status = 'completed';
switch($order_status){
    case 'completed':
        send_email_notification();
    case 'canceled':
        record_order_information();
        break;
    default:
        break;
}

In the above code, when the order status is completed, the send_email_notification() function will be called first, and if the order status is canceled, only the record_order_information() function will be called. . In this case, we do not need to use a break statement to end the execution of each branch.

It should be noted that if the break statement is not used, the program will continue to execute subsequent branches. If the execution of the current branch affects the execution of subsequent branches, the program will have a logic error.

Summary

When we write PHP programs, it is very common to use switch statements. Usually at the end of each branch, we will use the break statement to end the execution of the branch. However, in some cases, we need to let the program continue to execute subsequent branches, and in this case, we do not need to use the break statement.

When using the switch statement, you must pay attention to the logical relationship of the program to ensure that no logical errors are caused by not using the break statement.

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