Arithmetic limitations

Expect the unexpected:

Figure 98. Strange things I Slide presentation 
byte count = 91;   // o.K.

int i = 91;

byte count2 = i;   // Compile error: Incompatible types
                   // Required: byte Found: int

byte points = 130; // Compile error: Incompatible types
                   // Required: byte Found: int

Figure 99. Strange things II Slide presentation 
final int i = 91;

byte count = i;   //  o.K.

Why not generally using float / double in favour of seemingly more limited byte, short, int, long for arithmetics?

Figure 100. Limited precision Slide presentation 
float float2Power31 = Integer.MAX_VALUE + 1f; // 2^31

float floatDoubleMAX_VALUE = 2 * float2Power31 * float2Power31 - 1f; // 2^63 - 1

System.out.format( "   Float value: %f\n", floatDoubleMAX_VALUE);
System.out.println("Expected value: "   +  Long.MAX_VALUE);

Result:

   Float value:  9223372036854776000.000000
Expected value: -9223372036854775807
------------------------------------------
    Difference:                  193

Figure 101. Nearest float to 2.1 Slide presentation 
//Print 15 fractional digits
DecimalFormat df = new DecimalFormat("#.###############");

System.out.println(df.format(Float.intBitsToFloat(
  0b0_10000000_00001100110011001100110
)));

// The smallest possible step above previous value
System.out.println(df.format(Float.intBitsToFloat(
  0b0_10000000_00001100110011001100111
)));
 
2.099999904632568
2.100000143051147

Figure 102. FloatConverter Slide presentation
FloatConverter

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