how to generate number and characters together randomly. I know how to generate numbers randomly, but not getting anywhere with random character generation.
If you can pick a random letter and you pick a random integer, you can pick a random letter or integer, depending on the probability distribution you want. An example:
for (int i = 0; i < stringLength; i++)
int randomNumber = /* number from 0 to 35 */
if (randomNumber < 10)
c = /* pick random digit */
c = /* pick random letter */
// add c to end of randomString
I really don't like all these hacks based on the internal representation of chars, and what about the non-alphanumeric chars that sit in spaces between the alphabetics in ASCII/Unicode? Here's a good Java way to do it:
Create a char array containing all the valid symbols you want to use (digits, upper/lower case letters, selected punctuation etc). Use your random integers as indexes into the array to select random chars.