Operators
System.out.print(9 / 3); // Outputs 3
System.out.print(9 % 3); // Outputs 0
System.out.print(10 / 3); // Outputs 3
System.out.print(10 % 3); // Outputs 1
System.out.print(11 / 3); // Outputs 3
System.out.print(11 % 3); // Outputs 2
System.out.print(12 / 3); // Outputs 4
System.out.print(12 % 3); // Outputs 0
Numeric Promotion Rules
1. If two values have different
data types, Java will automatically promote one of the values to the larger of
the two data types.
2. If one of the values is
integral and the other is floating-point, Java will automatically promote the
integral value to the floating-point value’s data type.
3. Smaller data types, namely byte,
short, and char, are first promoted to int any time they’re used with a Java
binary arithmetic operator, even if neither of the operands is int.
4. After all promotion has
occurred and the operands have the same data type, the resulting value will have
the same data type as its promoted operands.
What is the data type of x / y?
short x = 10;
short y = 3;
In this case, we must apply the
third rule, namely that x and y will both be promoted to int before the
operation, resulting in an output of type int.
What is the data type of x * y / z?
short x = 14;
float y = 13;
double z = 30;
we evaluate the multiple and
division from left-to-right.In this case, we must apply all of the rules.
First, x will automatically be promoted to int solely because it is a short and
it is being used in an arithmetic binary operation. The promoted x value will
then be automatically promoted to a float so that it can be multiplied with y.
The result of x * y will then be automatically.
1.Increment/ Decrement
- For the final variables we can’t apply increment or decrement operators
final int i=10;
i++;
(or)
i=20;
Test.java:8: error: cannot assign a
value to final variable i
i++;
^
- We can apply increment or decrement operators even for floating point data types also.
double d = 10.5;
d++;
System.out.println(d);// 11.5
How this following expression is evaluated?
int x = 3;
int y = ++x * 5 / x-- + --x;
System.out.println("x is " + x);
System.out.println("y is " + y);
int y = 4 * 5 / x-- + --x; // x assigned value of 4
int y = 4 * 5 / 4 + --x; // x assigned value of 3
int y = 4 * 5 / 4 + 2; // x assigned value of 2
we evaluate the multiple and division
from left-to-right, and finish with the addition.The result is then printed: x
is 2 & y is 7
Does it work?
long t = 192301398193810323; // DOES NOT COMPILE
It does not compile because Java
interprets the literal as an int and notices that the value is larger than int
allows. The literal would need a postfi x L to be considered a long
short x = 10;
short y = 3;
short z = x * y; // DOES NOT COMPILE
short x = 10;
short y = 3;
short z = (short)(x * y);
long x = 10;
int y = 5;
y = y * x; // DOES NOT COMPILE
Based on the last two sections,
you should be able to spot the problem in the last line.This last line could be
fi xed with an explicit cast to (int), but there’s a better way using the
compound assignment operator:
long x = 10;
int y = 5;
y *= x;
The compound operator will first
cast x to a long, apply the multiplication of two long values, and then cast
the result to an int.
long x = 5;
long y = (x=3);
System.out.println(x); // Outputs 3
System.out.println(y); // Also, outputs 3
Infinity and -Infinity
- In Integer Arthematic (byte,int,short), if any thing divide 0 will get R.E: A.E: Divide by 0.
- But In Floating point arthematic, if any thing didvide by 0.0, we will get Infinity/ -Infinity
System.out.println(10 /
0.0); // Infinity
System.out.println(-10 /
0.0);// -Infinity
NaN – Not a Number
- In Integer Arthematic (byte,int,short), 0 divide 0 will get R.E: A.E: Divide by 0.
- But In Floating point arthematic, 0 divide by 0.0, we will get Nan (no -Nan is there)
System.out.println(0.0 /
0.0); // NaN
System.out.println(-0.0 /
0.0);// NaN
Equality Operators (==)
The comparisons for equality are
limited to these three cases, so you cannot mix and match types. For example,
each of the following would result in a compiler error:
boolean x = true == 3; // DOES NOT COMPILE
boolean y = false != "Giraffe"; // DOES NOT COMPILE
boolean z = 3 == "Kangaroo"; // DOES NOT COMPILE
Conditional Statements
int x = 1;
if(x) { // DOES NOT COMPILE
...
}
int x = 1;
if(x = 5) { // DOES NOT COMPILE
...
}
System.out.println((y > 5) ? 21 : "Zebra");
int animal = (y < 91) ? 9 : "Horse"; // DOES NOT
COMPILE
^ (X-OR) - Homogeneous are FALSE(T,T F,F), Heterogeneous are
TRUE(T,F F,T)
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