formatting using printf

[P Teng]

Can some one please explain the output caused by line 1

  class FormatEx1 {


    public static void main(String[] args) {
        
        int i1 = 12345;
        int i2 = -12345;
        float f1 = -98.56f;
        String s1 = "hello world";
        
        System.out.printf("%1$7d",i1);
        System.out.println();
        System.out.printf("%1$(7f",f1); // line 1
        System.out.println();
        System.out.printf("%1$+2.5f",f1);
        System.out.println();
        System.out.printf("%1$+(5d",i1);
        System.out.println();
        System.out.printf("%1$+-5d",i2);
        System.out.println();
        System.out.printf("%1$,-5d",i2);
           
    }
} 

output is below. What causes 559998 to appear after the . instead of just 56

  12345
(98.559998)
-98.56000
+12345
-12345
-12,345
    

[Rob Spoor]

The way floating point numbers are handled on computers. In short, just like you can't represent 1/3 exactly in decimal (0.3333 is an approximation), you can't represent 0.56 or even 0.1 exactly in binary. See this.