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JVM Instructions 1

The Java core language includes five simple arithmetic operators: +,-,*,/,% (where % is the modulo operator).

In binary operations, if either the first or second operand is a floating point type and the other is an integer type, the integer operand will convert to floating point. If it involves two two different integer types, the result will be in the wider type.

The addition operator '+' adds numeric values and also performs string concatenation, as in

   String str = "ab"+"cde"

results in str reference the string"abcde". This is the only case of an overloaded operator in Java.

The dash '-' acts as the subtraction operator in "a - b" and subtracts b from a. However, it can also act as the unary minus operator that performs negation on a single number ( a = -b) .

The "a/b" division operator divides a by b according to these rules:

• if both a and b are integers the result is an integer with the remainder dropped
• if either a or b is a floating point type, the result is floating point.
• if a and b are integers and b is zero, an ArthmeticException error is thrown.
• If either a or b is a floating point type and b is zero, the result is
  • positive infinity if a is a non-zero positive value
  • negative infinity if a is a non-zero negative value
  • NaN if a is also zero.

See the Floating Point sections for details on how these anomalous values are actually represented.

The "a%b" modulo operator returns the remainder of a divided by b. For example,

   5%3

returns a value of 2. If either operand is floating point, the result will be the floating point remainder.

Note: The Math class method

   Math.IEEEremainder(double a,double b)

will also compute a remainder of a/b for two double type values according to the specific rules of the IEEE 754 standard. (See the Math class specifications.)

Note: There is no exponent operator such as a**b for a to the b power. Instead, you must use the Math class method Math.pow(double a,double b)that computes a to the b power and returns the result as a double type.

Latest update: Dec.12.2003

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