simulating a die roll

[tjlandry34]

#include<iostream>

using namespace std;
int roll(), rnum;
void main()
{
int i;
for (i = 1; i <=5; i++)

cout << "Your roll is : " << roll() << endl;

srand(1811);

} // main

int roll()
{

static int roll = 0;
int rnum;

rnum = rand();
roll = rnum % 6+1;
return roll;

}
Right now im tryign to create the roll of a die and then take the sum of the odd and the sum of the even rolls and display them. All i have at the moment is the roll of the die and im only geting values of 5 or 6 back.
any reason why this isnt working properly?

[RedXIII]

Are you new to C++ Programming? The question seems irrelevant, but I assure you, it isn't.

[tjlandry34]

i am fairly new yes i just started using it at the beginning of this semester

[RedXIII]

Alright then, so here's what it should look like. Also you should stay away from using namespaces, they're not good practice.

#include<iostream>

int roll();

void main()
{
    srand(1811);

    for (int i = 1; i <= 5; ++i)
    {
        std::cout << "Your roll is : " << roll() << std::endl;
    }
}

int roll()
{
    return rand() % (6 + 1);
}

Another thing you seem to be missing, is the problem. I don't see what you're problem is with this code. could you explain?

[tjlandry34]

just the out put isnt coming out i wanted it to it was only returning 5 or 6 but that was with any random number seed. and why isnt it good practice to use namespaces?

[tjlandry34]

would an if else statement work well for taking the sum of the even/odd rolls? i have to create a function to do both and i am curious if that would be the best/easiest path

[RedXIII]

You can still use it for small applications like you're doing here, but you should get used to it. Answer why is here...
http://stackoverflow.com/a/1452738

So be more specific, what is it exactly you're trying to accomplish?

[tjlandry34]

ok thanks. and i am trying to simulate the roll of a die using a function roll(). Then using two other functions i need to take the even numbers sum them up and display them in the main and take the sum of the odd rolls and display them in the main also.

[tjlandry34]

int addOdd(int odd)
{
static int odd;

if(roll()%2)

odd += roll();

return odd;

}

I am thinking that the odd function should look something like this but i am getting an error message saying redefinition of formal parameter

[RedXIII]

You can't declare a variable static inside a function, or method is why, because a variable inside a function or method can only be used inside of it.

[Disch]

You can't declare a variable static inside a function, or method is why

Have to correct you here.

You absolutely can make variables static inside of functions.

His problem is that he has two different variables named 'odd':

int addOdd(int odd)  // <- odd declared here as a parameter
{
static int odd;  // <- odd declared here AGAIN as a local 

The solution is to rename one of them.

[RedXIII]

Really? Forgive me for handing out false information then. Could you possible give the use for having static variables inside a function or method?

[cire]

A static variable retains it's value from function call to function call.

// http://ideone.com/cLC4Os
#include <iostream>

int f()
{
    static int n = 0;  // initialization is done only the first time the function is called

    return n++;
}

int main()
{
    for (unsigned i = 0; i < 20; ++i)
        std::cout << f() << '\n';
}

[tjlandry34]

int addOdd(int  odd)
{
	static int num1;

	if(roll()%2)
		num1 += roll();

return num1;

}

Thanks a lot. Now im trying to take the sum of the odd numbers of the rolls and return them to the main function, But all im getting is 0 when i try and display it

[tjlandry34]

also when i set my srand to srand(1181) i get a value of zero for one of my rolls

[Mats]

What do your entire code look like right now?

[tjlandry34]

I fixed the problem with the roll. and here is what i have so far.

	#include<iostream>

	using namespace std;
	int roll(), addOdd(int odd);
	void main()
{
	int i;
	
	srand(1181);

	for (i = 1; i <=5; i++)
	{
	cout << "Your roll is : " << roll() << endl;
	}
	cout << "The sum of the odd numbers is: " << addOdd(roll()) << endl;
	cout << "The sum of the even numbers is: "<< endl;

} // main

int roll()
{
return (rand() % 6)+1;
}

int addOdd(int  odd)
{
	static int num1 = 0;

	if(roll()%2 )
		num1 += roll();

return num1;

}

[germanchocolate]

tjlandry34 wrote:

I fixed the problem with the roll. and here is what i have so far.

Try this:

#include<iostream>

using namespace std;

int roll();

void main() {
	int i;
	int odd=0, even=0;

	srand(1181);

	for(i = 1; i <=5; i++) {
		int r = roll();
		cout << "Your roll is : " << r << endl;
		if(r % 2) 
			even++;
		else
			odd++;
	}
	cout << "The sum of the odd numbers is: " << odd << endl;
	cout << "The sum of the even numbers is: "<< even << endl;

}

int roll() {
	return (rand() % 6)+1;
}

[tjlandry34]

Okay but you arent taking the sum of the odd and even numbers you are just simply telling how many there are out of the five rolls

[germanchocolate]

tjlandry34 wrote:

Okay but you arent taking the sum of the odd and even numbers you are just simply telling how many there are out of the five rolls

Oh, my bad. I thought you wanted how many times you rolled an odd number and vice versa.

If you want the total of each, try this:

if(r % 2) 
			even += r;
		else
			odd += r;

instead of

if(r % 2) 
			even++;
		else
			odd++;