What will be the output of the following C and Java programs?

C/JAVA:
int sum = 0;
for(int i=0;i<3;i++)
sum+=sum++;

Now print the value of sum

Answer...
C:
7
Java:
0

Why?...

cookbook

have a look at http://pleac.sourceforge.net/, thinking/working hard to contribute (Java & C++)  

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Stupid Me, System.currentTimeMills()

for(int j=0;j<100;j++)
{
    java.util.Random rnd = new java.util.Random(System.currentTimeMillis());
    for(int i=0;i<100;i++)
    {
        System.out.print(rnd.nextInt(10)+"");
    }
    System.out.println();
}

please don't expect the above program to give 100 different sets of 100 random numbers, there will be repetitions like anything. why?
First: for a particular seed a Random number generator should give same set of numbers, when ever it is run,
Second: our computers are fast enough to finish execution in micro seconds

so the generation of 100 numbers takes few micro seconds and the System.currentTimeMills() has resolution in milliseconds so, a week of stupid searching and debugging, here is a post.

how to fix it:-
use new Random(); forget about seed, this produces 100 different sets of 100 random numbers.

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