Differences between math. Random () and Java. util. Random () in Java

Today, I suddenly remembered the problem of Random Number Generation in Java. I tried it on the machine and found a difference. Here I will summarize it;

Directly calling math. Random () is to generate a random number between 0 and 1,

If you use

Java. util. random random = new random (); random. nextint () generates a long integer random number and is the same as the previous one. If it is generated later, it will not be the same. For example:

For (INT I = 0; I <10; I ++ ){
Random random = new random ();
Thread. Sleep (100 );
System. Out. Print (INT) random. nextint (100) + "");
}

Is to generate different random long numbers.

If you want to use Java. util. Random () to generate a random number within a specified range, evaluate the modulo operation and perform some processing.

 

you can also use random. nextint (100) to generate a random number less than 100. generally, nextint (range) is recommended. If it is not a large number of operations, math can be used. random now (because it can be relatively slow and rounded up after floating point)