I
I and II
I and III
II and III
第1题:
In the following statements about functional dependency, which one is incorrect?
A.If X→Y and Y→Z, then X→Z.
B.If X→Y and, then X→Y'.
C.If X→Y and, then X'→Y.
D.If, then X→X'.
第2题:
计算z的值,当x大于等于y时,z=x;否则z=y。下列语句错误的是( )
A.If x>=y Then z=x:z=y
B.If x>=y Then z=x Else z=y
C.z=y:If x>=y Then z=x
D.If x<y Then z=y Else z=x
第3题:
A. X x=new X();
Y y=new Y();
Z z=new Z();
y=(Y)x;
B. X x=new X();
Y y=new Y();
Z z=new Z();
x=(X)y;
C. X x=new X();
Y y=new Y();
Z z=new Z();
Z=(Z)x;
D. X x=new X();
Y y=new Y();
Z z=new Z();
W w=(W)x;
答案:D
解析:对象的强制类型转换的格式要求:"W w=(W)x;",只有D项符合
第4题:
Which statements, when inserted at the indicated position in the following code, will cause a runtime exception when attempting to run the program?() class A {} class B extends A {} class C extends A {} public class Q3ae4 { public static void main(String args[]) { A x = new A(); B y = new B(); C z = new C(); // insert statement here } }
第5题:
计算z的值,当x大于y时,z=x;否则z=y。下列语句错误的是
A.If x>=y Then z=x:z=y
B.If x>=y Then z=x Else z=y
C.z=y:If x>=y Then z=x
D.If x<=y Then z=y Else z=x
第6题:
下列函数定义不正确的是 ( )
A.int max { int x y,z; z=x>y? x: y }
B.int max(x,y) int x,y; { int z; z=x>y? x:y; return(z) }
C.int max(x,y) { int x,y z; z=x>y? x: y; return(z); }
D.int max( ) {}
第7题:
计算z的值,当x大于y时,z=x;否则z=y。下列语句错误的是( )
A. If x>=y Then z=x : z=y
B If x>=y Then z=x Else z=y
C. z=y : If x>=y Then z=x
D. If x<=y Then z=y Else z=x
第8题:
In the following statements about functional dependency, which one is incorrect?
A.Ifthen X→X'.
B.If X→Y andthen X→Y'.
C.If X→Y andthen X'→Y.
D.If X→Y and Y→Z, then X→Z.
第9题:
第10题:
表示关系X<=Y<=Z的JAVA语言表达式为()。