[kman42]

Code:

float progressIndicator;
progressIndicator=17/400*100;
NSLog(@"progressIndicator=%f",progressIndicator);

This results in progressIndicator being 0. What am I doing wrong?

kman

[jessejlt]

I still don't know objective-C well, but could it be as simple as missing parenthesis around the math?

progressIndicator = ( 17/400*100 );

[smeger]

Your code is standard C. In standard C, when you do integer math, you get an integer answer. Using all integers, 17/400 is zero (it's .0425 - truncate the non-integer portion and you get zero).

In standard C, an arithmetic operation's resulting type is dependent upon the types used within that operation. So, if you used 17.0 / 400 instead of 17 / 400, you'd get a fraction. Adding the '.0' tells the compiler "even though this number is an integer, I want you to treat it as a float". You could get the same result using (float)17 / 400.

The rule of thumb when using constants in a math expression is: If you want the answer to be a float, use constants that are explicitly floats. If not, don't.

For more info, consult any book about C and look for the section on 'expressions'.

[kman42]

Originally posted by smeger:
Your code is standard C. In standard C, when you do integer math, you get an integer answer. Using all integers, 17/400 is zero (it's .0425 - truncate the non-integer portion and you get zero).

In standard C, an arithmetic operation's resulting type is dependent upon the types used within that operation. So, if you used 17.0 / 400 instead of 17 / 400, you'd get a fraction. Adding the '.0' tells the compiler "even though this number is an integer, I want you to treat it as a float". You could get the same result using (float)17 / 400.

The rule of thumb when using constants in a math expression is: If you want the answer to be a float, use constants that are explicitly floats. If not, don't.

For more info, consult any book about C and look for the section on 'expressions'.

Thanks!