percentage of two int?

Question

I want to get two ints, one divided by the other to get a decimal or percentage. How can I get a percentage or decimal of these two ints? (I'm not sure if it is right.. I'm probably way off...) for example:

int correct = 25; int questionNum = 100; float percent = correct/questionNum *100; 

This is how I thought I could do it, but it didn't work... I want to make the decimal (if there is one) into a percent out of 100 for example in this case it is %25. any ideas anyone?

Here is the correct code (thanks to Salvatore Previti!):

float correct = 25; float questionNum = 100; float percent = (correct * 100.0f) / questionNum; 

(btw, I am making a project using this for a quiz checking program that is why I need the percentage or decimal)

Answer 1

If you don't add .0f it will be treated like it is an integer, and an integer division is a lot different from a floating point division indeed :)

float percent = (n * 100.0f) / v; 

If you need an integer out of this you can of course cast the float or the double again in integer.

int percent = (int)((n * 100.0f) / v); 

If you know your n value is less than 21474836 (that is (2 ^ 31 / 100)), you can do all using integer operations.

int percent = (n * 100) / v; 

If you get NaN is because wathever you do you cannot divide for zero of course... it doesn't make sense.

Answer 2

Two options:

Do the division after the multiplication:

int n = 25; int v = 100; int percent = n * 100 / v; 

Convert an int to a float before dividing

int n = 25; int v = 100; float percent = n * 100f / v; //Or: //  float percent = (float) n * 100 / v; //  float percent = n * 100 / (float) v;