Think in Java 翻书01_基本数据类型隐式转换

以你之姓@ 2022-03-12 12:18 32阅读 0赞

### 列表 ###

//: PrimitiveOverloading.java
    // Promotion of primitives and overloading
    
    public class PrimitiveOverloading {
        // boolean can't be automatically converted
        static void prt(String s) {
            System.out.println(s);
        }
        
    void f1(char x) { prt("f1(char)"); }
    void f1(byte x) { prt("f1(byte)"); }
    void f1(short x) { prt("f1(short)"); }
    void f1(int x) { prt("f1(int)"); }
    void f1(long x) { prt("f1(long)"); }
    void f1(float x) { prt("f1(float)"); }
    void f1(double x) { prt("f1(double)"); }
    void f2(byte x) { prt("f2(byte)"); }
    void f2(short x) { prt("f2(short)"); }
    void f2(int x) { prt("f2(int)"); }
    void f2(long x) { prt("f2(long)"); }
    void f2(float x) { prt("f2(float)"); }
    void f2(double x) { prt("f2(double)"); }
    
    void f3(short x) { prt("f3(short)"); }
    void f3(int x) { prt("f3(int)"); }
    void f3(long x) { prt("f3(long)"); }
    void f3(float x) { prt("f3(float)"); }
    void f3(double x) { prt("f3(double)"); }
    void f4(int x) { prt("f4(int)"); }
    void f4(long x) { prt("f4(long)"); }
    void f4(float x) { prt("f4(float)"); }
    void f4(double x) { prt("f4(double)"); }
    void f5(long x) { prt("f5(long)"); }
    void f5(float x) { prt("f5(float)"); }
    void f5(double x) { prt("f5(double)"); }
    void f6(float x) { prt("f6(float)"); }
    void f6(double x) { prt("f6(double)"); }
    void f7(double x) { prt("f7(double)"); }
    
    void testConstVal() {
        prt("Testing with 5");
        f1(5);f2(5);f3(5);f4(5);f5(5);f6(5);f7(5);
    }
    
    void testChar() {
        char x = 'x';
        prt("char argument:");
        f1(x);f2(x);f3(x);f4(x);f5(x);f6(x);f7(x);
    }
    void testByte() {
        byte x = 0;
        prt("byte argument:");
        f1(x);f2(x);f3(x);f4(x);f5(x);f6(x);f7(x);
    }
    void testShort() {
        short x = 0;
        prt("short argument:");
        f1(x);f2(x);f3(x);f4(x);f5(x);f6(x);f7(x);
    }
    void testInt() {
        int x = 0;
        prt("int argument:");
        f1(x);f2(x);f3(x);f4(x);f5(x);f6(x);f7(x);
    }
    void testLong() {
        long x = 0;
        prt("long argument:");
        f1(x);f2(x);f3(x);f4(x);f5(x);f6(x);f7(x);
    }
    void testFloat() {
        float x = 0;
         100
        prt("float argument:");
        f1(x);f2(x);f3(x);f4(x);f5(x);f6(x);f7(x);
    }
    void testDouble() {
        double x = 0;
        prt("double argument:");
        f1(x);f2(x);f3(x);f4(x);f5(x);f6(x);f7(x);
    }
    
    
        public static void main(String[] args) {
            PrimitiveOverloading p =
            new PrimitiveOverloading();
            
            p.testConstVal();
            p.testChar();
            p.testByte();
            p.testShort();
            p.testInt();
            p.testLong();
            p.testFloat();
            p.testDouble();
        }
    }
    复制代码

### 输出 ###

Testing with 5
    f1(int)
    f2(int)
    f3(int)
    f4(int)
    f5(long)
    f6(float)
    f7(double)
    
    char argument:
    f1(char)
    f2(int)
    f3(int)
    f4(int)
    f5(long)
    f6(float)
    f7(double)
    
    byte argument:
    f1(byte)
    f2(byte)
    f3(short)
    f4(int)
    f5(long)
    f6(float)
    f7(double)
    short argument:
    f1(short)
    f2(short)
    f3(short)
    f4(int)
    f5(long)
    f6(float)
    f7(double)
    int argument:
    f1(int)
    f2(int)
    f3(int)
    f4(int)
    f5(long)
    f6(float)
    f7(double)
    
    long argument:
    f1(long)
    f2(long)
    f3(long)
    f4(long)
    f5(long)
    f6(float)
    f7(double)
    float argument:
    f1(float)
    f2(float)
    f3(float)
    f4(float)
    f5(float)
    f6(float)
    f7(double)
    double argument:
    f1(double)
    f2(double)
    f3(double)
    f4(double)
    f5(double)
    f6(double)
    f7(double)
    复制代码

### 结论 ###

byte - > short - > int - > long - > float - > double

char - > int