- Generate random integers in Java
- Generate a random number within a specific range
- Generate a series of random numbers
- There is more than one way to generate random numbers in Java. These notes show the most standard technique.
- To create a random number generator: java.util.Random rnd = new java.util.Random()
- To get a random integer: rnd.nextInt()
- To get a random long integer: rnd.nextLong()
- To get a random float: rnd.nextFloat()
- To get a random double: rnd.nextDouble()
- To get a random integer in the range 0 to n-1: rnd.nextInt(n)
- To get a random integer in the range low to high: rnd.nextInt(high-low+1) + low
- A loop with a priming read that multiplies numbers entered until 0 is entered:
Generating a series of random numbers
- Generating a series of 5 random integers:
java.util.Random rnd = new java.util.Random();
for (int i = 1; i <= 5; i++) {
System.out.println(rnd.nextInt());
}
- Generating a series of n random integers:
java.util.Random rnd = new java.util.Random();
for (int i = 1; i <= n; i++) {
System.out.println(rnd.nextInt());
}
- Generating a series of n random integers in the range low to high:
java.util.Random rnd = new java.util.Random();
int rangeSize = high - low + 1;
for (int i = 1; i <= n; i++) {
System.out.println(rnd.nextInt(rangeSize) + low);
}