Java程序中，表示“数值” 以及 指数表示法

1、表示数值

//: operators/Literals.java public class Literals { public static void main(String[] args) { int i1 = 0x2f; // Hexadecimal (lowercase) System.out.println("i1: " + Integer.toBinaryString(i1)); int i2 = 0X2F; // Hexadecimal (uppercase) System.out.println("i2: " + Integer.toBinaryString(i2)); int i3 = 0177; // Octal (leading zero) System.out.println("i3: " + Integer.toBinaryString(i3)); char c = 0xffff; // max char hex value System.out.println("c: " + Integer.toBinaryString(c)); byte b = 0x7f; // max byte hex value System.out.println("b: " + Integer.toBinaryString(b)); short s = 0x7fff; // max short hex value System.out.println("s: " + Integer.toBinaryString(s)); long n1 = 200L; // long suffix long n2 = 200l; // long suffix (but can be confusing) long n3 = 200; float f1 = 1; float f2 = 1F; // float suffix float f3 = 1f; // float suffix double d1 = 1d; // double suffix double d2 = 1D; // double suffix // (Hex and Octal also work with long) } } /* * Output: i1: 101111 i2: 101111 i3: 1111111 c: 1111111111111111 b: 1111111 s: * 111111111111111 */// :~  

 

2、表示指数

//: operators/Exponents.java // "e" means "10 to the power." public class Exponents { public static void main(String[] args) { // Uppercase and lowercase 'e' are the same: float expFloat = 1.39e-43f;//编译器通常会 expFloat = 1.39E-43f; System.out.println(expFloat); double expDouble = 47e47d; // 'd' is optional double expDouble2 = 47e47; // Automatically double System.out.println(expDouble); } } /* * Output: 1.39E-43 4.7E48 */// :~