Java double type
In this chapter you will learn:
double type
double represents double-precision numbers. double is 64-bit width and its range is from 4.9e-324 to 1.8e+308 approximately.
Here is a program that uses double variables to compute the area of a circle:
public class Main {
public static void main(String args[]) {
double pi, r, a;
/*from ja v a 2 s . com*/
r = 10.8888; // radius of circle
pi = 3.1415926; // pi, approximately
a = pi * r * r;
System.out.println("Area of circle is " + a);
}
}
The output:
double type Literals
double type numbers have decimal values with a fractional component.
They can be expressed in either standard or scientific notation.
Standard notation consists of a whole number component followed by a decimal point followed by a fractional component.
For example, 2.0, 3.14159, and 0.6667.
public class Main {
public static void main(String args[]) {
double d = 3.14159;
System.out.print(d);//3.14159
} //from ja v a2 s .c o m
}
Scientific notation uses a standard-notation, floating-point number plus a suffix that specifies a
power of 10 by which the number is to be multiplied.
The exponent is indicated by an E or e followed by a decimal number, which can be positive or negative.
For example, 6.02E23, 314159E-05, and 4e+100.
public class Main {
public static void main(String[] argv) {
double d1 = 6.022E23;
double d2 = 314159E-05;
double d3 = 2e+100;
//from j ava 2s. c om
System.out.println("d1 is " + d1);
System.out.println("d2 is " + d2);
System.out.println("d3 is " + d3);
}
}
The output generated by this program is shown here:
You can explicitly specify a double literal by appending a D or d.
public class Main {
public static void main(String args[]) {
double d = 3.14159D;
System.out.print(d);//3.14159
} /* ja v a2 s . com*/
}
Java's floating-point calculations are capable of returning
+infinity, -infinity, +0.0, -0.0,
and NaN
dividing a positive number by 0.0 returns +infinity.
For example, System.out.println(1.0/0.0); outputs Infinity.
public class Main{
public static void main(String[] args) {
System.out.println(1.0/0.0);/* java 2s . c o m*/
}
}
double Infinity
Dividing a negative number by 0.0 outputs -infinity.
For example, System.out.println(-1.0/0.0); outputs -Infinity.
public class Main{
public static void main(String[] args) {
System.out.println(-1.0/0.0);// j a v a 2s .c om
}
}
Output:
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