round

[filipe26]

hi i have an application written in c.What i want to do is :
if (dinheiro[0]==valor || dinheiro[1]==valor)
printf("\n->Maquina %d",i+1);

dinheiro and valor are float values and when have the same value dont enter in printf.

 

[Totte]

And what are the problem???

As i understand you will NOT print out when dinheiro = valor?

if((dinheiro[0] != valor) || (dinheiro[1] != valor))
printf("\n->Maquina %d",i+1);

this means: if dinheiro[0] is NOT equal to valor OR dinheiro[1] is NOT equal to valor THEN do printf(...)

Totte

 

[Totte]

By the way, to compare float values for equality might be less effective, a better way is to get the difference and determine if the difference is below a certain value which then is called equal.

This is usable when you're calculating the values with math and will catch "rounding"-errors.

Ex: FloatDiff = Float1 > Float2 ? Float1 - Float2 : Float2 - Float1;

This means:
IF Float1 IS LARGER THAN Float2
THEN set FloatDiff to (Float1 - Float2)
ELSE set FloatDiff to (Float2 - Float1)

FloatDiff will now hold the difference and now you can decide if it's low enough to call equal or not.

Totte

 

[filipe26]

and how i round a float value.For example i have 123.699992
i want to put in a variable the value 123.70

 

[2ffat]

You could multiply the floating point number by the number of decimal points you want (* 10), add .5, put the float to an integer, take it back to a float, then divide by the same number you multiplied it with.

float Number = 123.699992;
float NewNumber = Number * 20; // If you want to 2 decimal places
// NewNumber = 12369.9992...
NewNumber += .5; // NewNumber = 12370.4992...
int IntNumber = (int)NewNumber; // IntNumber = 12370
Number = (float)NewNumber); // Number = 12370
Number = Number / 20; // Number = 123.70

I'm doing this off the top of my head so it may be buggy. I'll leave it up to you to clean it up. I kept the steps separate to make it easier to see.

The problem stems from how most CPUs handle floating point.

James P. Cottingham

^{There's no place like 127.0.0.1.
There's no place like 127.0.0.1.}