someone godly at C helpz me please

[beramodk]

can a mod delete this thread please.
thanks

 

[dighn]

nan means not a number. you probably have an invalid operation somewhere. like division by 0, log 0 or something

 

[kamper]

Your code is hideous. Try using the Attach Code feature (so we can see the indentation) and using variable names that actually mean something. Then maybe someone will read it.

 

[Mayson]

Yeah, you get a problem when you take this path through your code:

int main()
{
double f;
double b;
double c = 1.0;
double pp = 0.6;
int coin;
int win = 0;
int n = 0;
int i;
int bet;

for (i = 0; i < N-1; i++)
{
c = log(c);
coin = rand() % 2;
if (pp > 0.5)
{

At the end of this part C = 0
Coin = some random number from 0 to 1 (let's say 1 in this case)
pp=.6

so we next go into this part

if (pp > 0.5)
{
bet = 1;
f = 2 * pp - 1;
b = f * c;
}

at the end of this section
bet = 1
f = 2 * pp -1 = .2
b = .2 * 0 = 0

Now if coin == 0 and bet == 1 (same error also happens if coin==1)
{
c -= b;
n++;
}

Which makes c = c -b = 0 - 0 = 0
N = 10000001


So when you go back through the for loop again at the beginning here:
c = log(c);
coin = rand() % 2;
if (pp > 0.5)

c = log(0) = - infinity

and there's your problem. You need to prevent your log(0) error with another case somewhere.

 

[Mayson]

Woops... good thing I didn't go through the trouble of trying to fix the code. Just noticed that it was due yesterday. Sorry.