Having difficulties locating a problem in the for loop

Question

I am writing a program where a user inputs the name of contestants and buys like a ticket for a competition. I am trying to figure out the percent chance for each contestant to win but for some reason its returning zero, here's the code

for(int i = 0; i < ticPurch.size(); i++){
    totalTics = ticPurch[i] + totalTics;                                              //Figuring out total amount of ticket bought
}
    cout << totalTics;

for (int i = 0; i < names.size(); i++){
    cout << "Contenstant "  << "   Chance of winning " << endl; 
    cout << names[i] << "   " << ((ticPurch.at(i))/(totalTics)) * 100 << " % " << endl; //Figuring out the total chance of winning 

}
    ticPurch is a vector of the the tickets each contestant bought and names is a vector for the contestants name. For some reason the percent is always returning zero and I don't know why

 return 0;

Answer 1

Dividing an integer by an integer gives you an integer , by truncation of the fractional part.

Since your values are less than one, your result will always be zero.

You could cast an operand to a floating-point type to get the calculation you wanted:

(ticPurch.at(i) / (double)totalTics) * 100

Then probably round this result, since you seem to want whole number results:

std::floor((ticPurch.at(i) / (double)totalTics) * 100)

My preferred approach, which avoids floating-point entirely (always nice!), is to multiply to the resolution of your calculation first :

(ticPurch.at(i) * 100) / totalTics

This will always round down , so be aware of that if you decided to go with, say, std::round (or std::ceil ) instead of std::floor in the example above. Arithmetic trickery can mimic those if needs be.

Now, instead of eg (3/5) * 100 (which is 0*100 (which is 0 )), you have eg (3*100)/5 (which is 300/5 (which is 60 )).