Floating Point Exception C++ Why and what is it?

Question

I'm building a program for the Euler projects question 3, and while that might not really matter as a result I'm current trying to make this code take a number and test if it is prime or not. Now then before I get to troubleshoot the function it gives me the error "floating point exception" right after inputting the number. Here's the code:

int main() {     int input;     cout << "Enter number: " << endl;     cin>> input;     int i = input/2;     int c;     for (i>0; i--;) {         c= input%i;         if (c==0 || i == 1)             cout << "not prime" << endl;         else             cout << "prime" << endl;     }     return 0; } 

so essentially why is it giving me a floating point exception and what does that even mean?

Answer 1

A "floating point number" is how computers usually represent numbers that are not integers -- basically, a number with a decimal point. In C++ you declare them with float instead of int. A floating point exception is an error that occurs when you try to do something impossible with a floating point number, such as divide by zero.

Answer 2

for (i>0; i--;) 

is probably wrong and should be

for (; i>0; i--) 

instead. Note where I put the semicolons. The condition goes in the middle, not at the start.