Generate a Random Number based on a range of values

[shaoen01]

Hi all,

I am trying to generate a range of random values from 0 to 1280. I tried searching on the Internet but didn't quite understand. I know rand()%10 will give me a range from 0-9.

But how should i do it to get from 0 to 1280? At the moment, i am trying to do a guess the number program where the number is given by the user and the program will need to guess.

So whenever say number>guessVal in guess() method then i will throw an exception of type class which does nothing. So my question is, can i go back to the head of the guess method to guess again or recursive from a catch block? Thanks

[_Superman_]

To generate a random number between 2 numbers, you can do this

int u = (double) rand() / (RAND_MAX + 1) * (range_max - range_min) + range_min;

[shaoen01]

Thanks superman, it works. Do you know how i can create a global variable such as an int[]?

[_Superman_]

declare int i[10]; outside any functions

[shaoen01]

I managed to do it for my int array[], but when i tried to declare a int count=0 outside like the int array[] as i wish to make it a global variable, it will give me an error when i try to access it within a function like count++? At the moment, my function does nothing meaningful as i was just testing it out.

int pastValues[1280];
int count=0;

int aaa(int i) {
count++;
}

My error message:
`count' undeclared (first use this function)

[_Superman_]

What you have done is perfect.
Make sure int count=0; comes before the function aaa.
Or try with a different name.

[shaoen01]

You are right. I think count is a reserved word, i changed count to bb and it works. Thanks

[laserlight]

I think count is a reserved word, i changed count to bb and it works.

count is not a reserved word, though it is conceivable that there could be a name conflict.

However, why do you want to use global variables here? With the given information, it seems that local variables with argument passing will suffice.

[jefranki]

If no other function needs access to count, you can use:

int pastValues[1280];

int aaa(int i)
{
	static int count = 0; //initiallizer, only does this once your whole program

	count++;
}

[kempofighter]

You've probably got a "using namespace std" somewhere that causes the name conflict with count. Someone else just had this problem fairly recently. That's just a guess on my part though. Another thing you can do is use namespaces. Don't create global variables. Define all variables within namespaces or classes.