Java Math abs() 方法和示例

绝对值是指与作为参数传递的数字相对应的正值。现在，极客你一定想知道它到底是什么意思，所以无论传递给计算的是正数还是负数，它都会被引用，在这两种情况下，计算都将发生在对应的正数上。因此，为了计算任何数字的绝对值，我们在Java中确实有一个指定的方法，称为abs()存在于Java.lang 包中的 Math 类中。

Java.lang.Math.abs()返回给定参数的绝对值。

• 如果参数不是负数，则返回参数。
• 如果参数是否定的，则返回参数的否定。

句法 ：

public static DataType abs(DataType a)

参数： Int、long、float或double值，其绝对值待确定

返回类型：此方法返回参数的绝对值。

抛出的异常：算术异常

Tip: One must be aware of generic return type as follows:

• If the argument is of double or float type: 
  • If the argument is positive zero or negative zero, the result is positive zero.
  • If the argument is infinite, the result is positive infinity.
  • If the argument is NaN, the result is NaN.
• If the argument is of int or long type: If the argument is equal to the value of Integer.MIN_VALUE or Long.MIN_VALUE, the most negative representable int or long value, the result is that same value, which is negative.

示例 1：

Java

// Java Program to Illustrate Absolute Method
// of Math Class
 
// Importing all Math classes
// from java.lang package
import java.lang.Math;
 
// Main class
class GFG {
   
    // Main driver method
    public static void main(String[] args)
    {
 
        // Custom integer input received from user
        int n = -7;
 
        // Printing value before applying absolute function
        System.out.println(
            "Without applying Math.abs() method : " + n);
 
        // Applying absolute math function and
        // storing it in integer variable
        int value = Math.abs(n);
 
        // Printing value after applying absolute function
        System.out.println(
            "With applying Math.abs() method : " + value);
    }
}

输出

Without applying Math.abs() method : -7
With applying Math.abs() method : 7

示例 2：

Java

// Java Program to Demonstrate Working of abs() method
// of Math class inside java.lang package
 
// Importing Math class
// from java.lang package
import java.lang.Math;
 
// Main class
class GFG {
 
    // Main driver method
    public static void main(String args[])
    {
        // Customly declaring and initializing all
        // arguments that ans() function takes
 
        // Float
        float a = 123.0f;
        float b = -34.2323f;
 
        // Double
        double c = -0.0;
        double d = -999.3456;
 
        // Integer
        int e = -123;
        int f = -0;
 
        // Long
        long g = -12345678;
        long h = 98765433;
 
        // abs() method taking float type as input
        System.out.println(Math.abs(a));
        System.out.println(Math.abs(b));
 
        // abs() method taking double type as input
        System.out.println(Math.abs(1.0 / 0));
        System.out.println(Math.abs(c));
        System.out.println(Math.abs(d));
 
        // abs() method taking int type as input
        System.out.println(Math.abs(e));
        System.out.println(Math.abs(f));
        System.out.println(Math.abs(Integer.MIN_VALUE));
 
        // abs() method taking long type as input
        System.out.println(Math.abs(g));
        System.out.println(Math.abs(h));
        System.out.println(Math.abs(Long.MIN_VALUE));
    }
}

输出

123.0
34.2323
Infinity
0.0
999.3456
123
0
-2147483648
12345678
98765433
-9223372036854775808