select (null or null),(null or 1),(null || 0),(-8 or 0);
select (null or null),(null or 1),(null || 0),(-8 or 0);
设有如下代码段 1 String s = null; 2 if ( s != null & s.length() > 0) 3 System.out.println("s != null & s.length() > 0"); 4 if ( s != null && s.length() > 0) 5 System.out.println("s != null & s.length() > 0"); 6 if ( s != null || s.length() > 0) 7 System.out.println("s != null & s.length() > 0"); 8 if ( s != null | s.length() > 0) 9 System.out.println("s != null | s.length() > 0"); 哪些行将抛出空指针异常?
设有如下代码段 1 String s = null; 2 if ( s != null & s.length() > 0) 3 System.out.println("s != null & s.length() > 0"); 4 if ( s != null && s.length() > 0) 5 System.out.println("s != null & s.length() > 0"); 6 if ( s != null || s.length() > 0) 7 System.out.println("s != null & s.length() > 0"); 8 if ( s != null | s.length() > 0) 9 System.out.println("s != null | s.length() > 0"); 哪些行将抛出空指针异常?
设有如下代码段 1 String s = null; 2 if ( s != null & s.length() > 0) 3 System.out.println("s != null & s.length() > 0"); 4 if ( s != null && s.length() > 0) 5 System.out.println("s != null & s.length() > 0"); 6 if ( s != null || s.length() > 0) 7 System.out.
设有如下代码段 1 String s = null; 2 if ( s != null & s.length() > 0) 3 System.out.println("s != null & s.length() > 0"); 4 if ( s != null && s.length() > 0) 5 System.out.println("s != null & s.length() > 0"); 6 if ( s != null || s.length() > 0) 7 System.out.
class Person{ static{ System.out.println(name); } private static String name = "hello"; } class Demo{ public static void main(String[] args){ Person p = null; } }
class Person{ static{ System.out.println(name); } private static String name = "hello"; } class Demo{ public static void main(String[] args){ Person p = null; } }
如下程序的输出结果是( )。public class Demo { public static void main(String[] args) { int value = 2010; changeValue(value); System.out.println(value); } public static void changeValue(int value){ value = 0; }} A: 2010 B: 0 C: null D: 编译出错
如下程序的输出结果是( )。public class Demo { public static void main(String[] args) { int value = 2010; changeValue(value); System.out.println(value); } public static void changeValue(int value){ value = 0; }} A: 2010 B: 0 C: null D: 编译出错
Null数据类型包含一个值,即 null。此值意味着"0",即数据等于“0”
Null数据类型包含一个值,即 null。此值意味着"0",即数据等于“0”
下列对数组赋值的语句正确的是( ) A: static a[4]={0,0,0,0} B: int a[4]={0*4} C: static a[4]=0 D: static a[4];a=0;
下列对数组赋值的语句正确的是( ) A: static a[4]={0,0,0,0} B: int a[4]={0*4} C: static a[4]=0 D: static a[4];a=0;
以下对二维数组a进行正确初始化的是(). A: static char word[]='Turbo\0'; B: static char word[]={'T','u','r','b','o','\0'}; C: static char word[]={"Turbo\0"}; D: static char word[]="Turbo\0";
以下对二维数组a进行正确初始化的是(). A: static char word[]='Turbo\0'; B: static char word[]={'T','u','r','b','o','\0'}; C: static char word[]={"Turbo\0"}; D: static char word[]="Turbo\0";
设有如下代码public class Test{ static int x[] = new int[10]; public static void main ( String arg[] ) { System.out.println(x[0]); }}哪个叙述为真? A: 运行出错 B: 出现编译错误 C: 输出 0 D: 输出 null
设有如下代码public class Test{ static int x[] = new int[10]; public static void main ( String arg[] ) { System.out.println(x[0]); }}哪个叙述为真? A: 运行出错 B: 出现编译错误 C: 输出 0 D: 输出 null
以下不是c语言的关键字的是( ) A: case B: typedef C: static D: null
以下不是c语言的关键字的是( ) A: case B: typedef C: static D: null