Make a float only show two decimal places

Question

It is not a matter of how the number is stored, it is a matter of how you are displaying it. When converting it to a string you must round to the desired precision, which in your case is two decimal places.

E.g.:

NSString* formattedNumber = [NSString stringWithFormat:@"%.02f", myFloat];

%.02f tells the formatter that you will be formatting a float (%f) and, that should be rounded to two places, and should be padded with 0s.

E.g.:

%f = 25.000000
%.f = 25
%.02f = 25.00

Here are few corrections-

//for 3145.559706

---

Swift 3

let num: CGFloat = 3145.559706
print(String(format: "%f", num)) = 3145.559706
print(String(format: "%.f", num)) = 3145
print(String(format: "%.1f", num)) = 3145.6
print(String(format: "%.2f", num)) = 3145.56
print(String(format: "%.02f", num)) = 3145.56 // which is equal to @"%.2f"
print(String(format: "%.3f", num)) = 3145.560
print(String(format: "%.03f", num)) = 3145.560 // which is equal to @"%.3f"

---

Obj-C

@"%f"    = 3145.559706
@"%.f"   = 3146
@"%.1f"  = 3145.6
@"%.2f"  = 3145.56
@"%.02f" = 3145.56 // which is equal to @"%.2f"
@"%.3f"  = 3145.560
@"%.03f" = 3145.560 // which is equal to @"%.3f"

and so on...

You can also try using NSNumberFormatter:

NSNumberFormatter* nf = [[[NSNumberFormatter alloc] init] autorelease];
nf.positiveFormat = @"0.##";
NSString* s = [nf stringFromNumber: [NSNumber numberWithFloat: myFloat]];

You may need to also set the negative format, but I think it's smart enough to figure it out.

I made a swift extension based on above answers

extension Float {
    func round(decimalPlace:Int)->Float{
        let format = NSString(format: "%%.%if", decimalPlace)
        let string = NSString(format: format, self)
        return Float(atof(string.UTF8String))
    }
}

usage:

let floatOne:Float = 3.1415926
let floatTwo:Float = 3.1425934
print(floatOne.round(2) == floatTwo.round(2))
// should be true