已知如下定义:String s = "story"; 下面哪个表达式是合法的()
A.s += "books"
B. char c = s[1]
C. int len = s.length
D. String t = s.toLowerCase()
A.s += "books"
B. char c = s[1]
C. int len = s.length
D. String t = s.toLowerCase()
A.im s as integer
B.im s as string
C.im s as double
D.im s as long
下列是一个类的定义,将程序段补充完整。 class A { String s; 【 】int a=66; A(String sl) { s=sl;} static int geta() { return a;} }
A.正确运行,输出:A
B.编译时发生错误
C.正确运行,输出:B
D.运行时引发异常
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==butt)
{
String s=null;
try
{
if((new FileDialog()).file!=null)
{
String filename=FileDialog.file.getName();
RandomAccessFile in=new()(filename,"r");
while((s=in.readLine())!=null)
textA.append(s+"/n");
();
}
}
catch(FileNotFoundException e1){}
catch(IOException e2){}
}
}
已知重油的元素分析结果如下:
C:85.5% H:11.3% O:2.0% N:0.2% S:1.0%
试计算:
S={x|x为素数且x<100},在S上定义运算“*”,“”如下:
x*y=max(x,y),xy>1cm(x,y)(x,y的最小公倍数).
试问:
已知化合物A、B属于同系物,其蒸气压如下:
温度/℃ | p_A^S/kPa | p_B^S/kPa |
65.6 | 80.0 | 66.66 |
93.3 | 133.32 | 126.66 |
假设化合物组成理想溶液,计算:79.4℃,xA=0.500时,达到汽液平衡时组分A的气相摩尔分数和系统的总压。已知:Clausius-Clapeyron方程为。