java --基本数据类型间的转换

Posted 2020-10-05 Constructor

public class changetype {
     public static void main(String[] args)
     {  
        String ar = "true";  //String转 boolean ,只要不是"true",结果即为false;
        boolean ar1 = Boolean.parseBoolean(ar);
        if(ar1)
        {
            System.out.println("true");   //结果为true;
        }
        
        String str = "12";    //String 转   int
        int m = Integer.parseInt(str);
        System.out.println(m);
        
        String str0 = "12.6";             //string转换成double
        double x = Double.parseDouble(str0);
        System.out.println(x);
        
        int y = 5;
        String str1 = y+"";
        System.out.println(str1);
        
        int flag = 100;         //int转String,任何类型与字符串连接将变为字符串类型。不推荐使用
        String a = flag+"";
        System.out.println(a); 
        
        int flag0 = 200;               //int 转String 利用String.valueOf();
        String str3 = String.valueOf(flag0);
        System.out.println(str3);
        
        float h = 12.6f;  //  float 转 int ，由高到低必须进行强制类型转换，损失精度变为12
        int w =(int)h;
        System.out.println(w);    //结果为12
        
        float c = 89.6666f;
        double s = c;
        System.out.println(s);    //结果为89.666677987979
        
        double e = 78.999999999;
        float o = (float)e;
        System.out.println(o);   //结果为79
        
        
        
        
     }}