j02050501.java

经典java教材《java完美经典》一书中源码的完全收集

import java.lang.*;

class j02050501
{
  public static void main(String para[])
  {
    char Ch1,Ch2;
    Ch1 = 'A';
    Ch2 =(char)(Ch1 + 32); //Ch1 + 32 结果值为 int 型态
    // 前一个() 表示强制转型，后一个()表示里面的表达式要先做完       
    System.out.println("Ch1 + 32 = " + Ch2);   //65+32=97 ==>'a'

    int A1 = 56;
    byte B1 = 13;    //两个都是整数，也都不是long
    System.out.println( A1 + "/" + B1 + " = " + A1/B1 );
                                        //商数一定是 int
    System.out.println( (float)A1 + "/" + B1 + " = " + (float)A1 /B1 );
                                    //A1 转为 float，商数会是 float
    
    double A2 = A1;    //一个是 double
    System.out.println( A2 + "/" + B1 + " = " + A2/B1 );   	
  	                                    //商数一定是 double
  	A2 = 39;
  	System.out.println( A2 + "/" + B1 + " = " + A2/B1 );
  	                   //就算整除，商数也一定是 double                                                	
  }
}