PHP Switch Understanding

Prior to doing the project encountered a problem, the code is roughly as follows:

Switch ($a) {case $a >=1000 && $a <5000:echo "vip1";    Break        Case $a >=5000 && $a <=10000:echo "VIP2";    Break Default:echo "Vipx";

If $ A >0 is not a problem, when $ A =0, the problem will come, the program will output: VIP1;

Later, it should be the following:

The function of switch in PHP is: Choose to execute a block of code, which works as follows:

　1. A one-time calculation of expressions (usually variables);

2. Compare the value of the variable with the value of case in the switch structure;

3. If the value of the variable is equal to the value of the case, the code associated with it is executed;

4. When the code finishes executing, the break statement prevents the code from jumping into the next case to continue execution;

5. If there is no case condition to match, execute the code in default;

Instance code:

That is, when $ A =0, the first case first operation, $a >=1000 && $a <5000 Of course is false, and then 0 vs. false, which is true, so returned "VIP1";

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PHP Switch Understanding