class Student extends Person{ String sID;
public Student(String n,String s,int a,String sid){ super(n,s,a); sID = sid; }
void showID(){
System.out.println(\ }}
µÚ6ÕÂ
Ò»¡¢Ñ¡ÔñÌâ
1£®¸ø³öÏÂÃæ³ÌÐò´úÂ룺
byte[] a1, a2[]; byte a3[][]; byte[][] a4;
ÏÂÁÐÊý×é²Ù×÷Óï¾äÖÐÄÄÒ»¸öÊDz»ÕýÈ·µÄ£¿£¨ A £© A£®a2 = a1 B£®a2 = a3 C£®a2 = a4 D£®a3 = a4 ¡¾½âÎö¡¿Ö»ÓÐάÊýÏàͬµÄÊý×é²ÅÄÜÏ໥¸³Öµ¡£ 2£®¹ØÓÚÊý×飬ÏÂÁÐ˵·¨Öв»ÕýÈ·µÄÊÇ£¨ C £©¡£
A£®Êý×éÊÇ×î¼òµ¥µÄ¸´ºÏÊý¾ÝÀàÐÍ£¬ÊÇһϵÁÐÊý¾ÝµÄ¼¯ºÏ B£®Êý×éÔªËØ¿ÉÒÔÊÇ»ù±¾Êý¾ÝÀàÐÍ¡¢¶ÔÏó»òÆäËûÊý×é C£®¶¨ÒåÊý×éʱ±ØÐë·ÖÅäÄÚ´æ
D£®Ò»¸öÊý×éÖÐËùÓÐÔªËØ¶¼±ØÐë¾ßÓÐÏàͬµÄÊý¾ÝÀàÐÍ
¡¾½âÎö¡¿Êý×éÔªËØ¿ÉÒÔÊÇ»ù±¾Êý¾ÝÀàÐÍ¡¢¶ÔÏó»òÆäËûÊý×é¡£ 3£®ÉèÓÐÏÂÁÐÊý×鶨ÒåÓï¾ä£º
int a[] = {1, 2, 3};
Ôò¶Ô´ËÓï¾äµÄÐðÊö´íÎóµÄÊÇ£¨ C £©¡£ A£®¶¨ÒåÁËÒ»¸öÃûΪaµÄһάÊý×é B£®aÊý×éÓÐ3¸öÔªËØ C£®aÊý×éÔªËØµÄϱêΪ1¡«3 D£®Êý×éÖÐÿ¸öÔªËØµÄÀàÐͶ¼ÊÇÕûÊý ¡¾½âÎö¡¿Êý×éÔªËØµÄϱêÊÇ´Ó0¿ªÊ¼µÄ¡£
4£®Ö´ÐÐÓï¾ä£ºint[] x = new int[20];ºó£¬ÏÂÃæÄĸö˵·¨ÊÇÕýÈ·µÄ£¿£¨ C £© A£®x[19]Ϊ¿Õ B£®x[19]䶨Òå C£®x[19]Ϊ0 D£®x[0]Ϊ¿Õ ¡¾½âÎö¡¿´ËÓï¾ä¶¨ÒåÁËxÊý×éºó£¬x[0]~x[19]µÄֵȫ²¿Îª0¡£ 5£®ÏÂÃæ´úÂëÔËÐкóµÄÊä³ö½á¹ûΪ£¨ A £©¡£
public class X6_1_5 {
public static void main(String[] args) { AB aa = new AB(); AB bb; bb = aa;
System.out.println(bb.equals(aa)); }}
class AB{ int x = 100; } A£®true
B£®false C£®±àÒë´íÎó D£®100
21
¡¾½âÎö¡¿Í¬Ò»¸öÀàµÄÁ½¸ö¶ÔÏó¿ÉÒÔÏ໥¸³Öµ£¬¸³ÖµºóÁ½¸ö¶ÔÏó¾ßÓÐÏàͬµÄ´æ´¢¿Õ¼ä£¬Òò´ËÊÇÏàͬµÄ¡£
6£®ÒÑÖªÓж¨Ò壺String s=\£¬ÏÂÃæÄĸö±í´ïʽÕýÈ·£¿£¨ A £© A£®s += \ B£®char c = s[1]; C£®int len = s.length; D£®String s = s.toLowerCase();
¡¾½âÎö¡¿×Ö·û´®¶ÔÏó¿ÉÒÔÖ´ÐС°+=¡±ÔËË㣬µ«²»ÄÜÓÃs[1]ÕâÖÖ·½Ê½È¡ÆäÖеÄ×Ö·û£¬Ò²²»ÄÜÓÃlengthÇóËüµÄ³¤¶È£¬¿ÉÒÔÓÃlength()ÇóÆä³¤¶È£¬Òò´ËB¡¢C²»ÕýÈ·£¬²»ÄÜÔٴζ¨Òås×Ö·û´®£¬Òò´ËD²»ÕýÈ·¡£ ¶þ¡¢Ìî¿ÕÌâ
1£® ObjectÀà ÊÇËùÓÐÀàµÄÖ±½Ó»ò¼ä½Ó¸¸À࣬ËüÔÚ java.lang °üÖС£ 2£®SystemÀàÊÇÒ»¸ö¹¦ÄÜÇ¿´ó¡¢·Ç³£ÓÐÓõÄÌØÊâµÄÀ࣬ËüÌṩÁË ±ê×¼ÊäÈë/Êä³ö ¡¢ ÔËÐÐʱ ϵͳÐÅÏ¢µÈÖØÒª¹¤¾ß¡£Õâ¸öÀ಻ÄÜ ÊµÀý»¯ £¬¼´²»ÄÜ´´½¨SystemÀàµÄ¶ÔÏó£¬ËùÒÔËüËùÓеÄÊôÐԺͷ½·¨¶¼ÊÇ static ÀàÐÍ£¬ÒýÓÃʱÒÔÀàÃûSystemΪǰ׺¼´¿É¡£
3£®AppletÓÉä¯ÀÀÆ÷×Ô¶¯µ÷ÓõÄÖ÷Òª·½·¨ init £¬ start £¬ stop ºÍ destroy ·Ö±ð¶ÔÓ¦ÁËApplet´Ó³õʼ»¯¡¢Æô¶¯¡¢ÔÝÍ£µ½ÏûÍöµÄÉúÃüÖÜÆÚµÄ¸÷¸ö½×¶Î ¡£
4£®Êý×éÊÇÒ»ÖÖ ¸´ºÏ Êý¾ÝÀàÐÍ£¬ÔÚJavaÖУ¬Êý×éÊÇ×÷Ϊ ¶ÔÏó À´´¦ÀíµÄ¡£Êý×éÊÇÓÐÏÞÔªËØµÄÓÐÐò¼¯ºÏ£¬Êý×éÖеÄÔªËØ¾ßÓÐÏàͬµÄ Êý¾ÝÀàÐÍ £¬²¢¿ÉÓÃͳһµÄ Êý×éÃû ºÍ ϱê À´Î¨Ò»È·¶¨ÆäÔªËØ¡£
6£®Êý×é³õʼ»¯°üÀ¨ ¾²Ì¬ ³õʼ»¯ºÍ ¶¯Ì¬ ³õʼ»¯Á½ÖÖ·½Ê½¡£ 7£®ÀûÓà System ÀàÖÐµÄ arraycopy() ·½·¨¿ÉÒÔʵÏÖÊý×éÔªËØµÄ¸´ÖÆ£»ÀûÓà Arrays ÀàÖÐµÄ sort() ºÍ binarySearch() ·½·¨¿ÉÒÔʵÏÖ¶ÔÊý×éÔªËØµÄÅÅÐò¡¢²éÕҵȲÙ×÷¡£ 8£®JavaÓïÑÔÌṩÁËÁ½ÖÖ¾ßÓв»Í¬²Ù×÷·½Ê½µÄ×Ö·û´®Àࣺ String ÀàºÍ StringBuffer Àà¡£ËüÃǶ¼ÊÇ java.lang.Object µÄ×ÓÀà¡£ Èý¡¢Ð´³öÏÂÁгÌÐòµÄÔËÐнá¹û 1£®public class X6_3_1 {
public static void main(String[] args) { int a[]={12,39,26,41,55,63,72,40,83,95}; int i1=0,i2=0;
for(int i=0;i System.out.println(i1+\ } ¡¾ÔËÐнá¹û¡¿ 6 4 2£®public class X6_3_2 { public static void main(String[] args) { int a[]={36,25,48,14,55,40,32,66}; int b1,b2; b1=b2=a[0]; for(int i=1;i if ( b1 >b2 ) b2=b1; 22 b1=a[i]; } System.out.println(b1+\ } } ¡¾ÔËÐнá¹û¡¿ 66 55 3£®public class X6_3_3 { public static void main(String[] args) { int a[]={36,25,48,14,55,40,32,66 }; int b1,b2; b1=b2=a[0]; for (int i=1;i if ( b1 System.out.println(b1+\ } } ¡¾ÔËÐнá¹û¡¿ 14 25 4£®public class X6_3_4 { public static void main(String[] args) { String str = \ char[] a =str.toCharArray(); int i1 =0, i2=0, i; for(i=0;i System.out.println(i1+\ }} ¡¾ÔËÐнá¹û¡¿ 4 3 5£®public class X6_3_5 { public static void main(String[] args) { String str =\ char[] a = str.toCharArray(); int b[] = new int[5],i; for(i=0;i case 'a': b[0] ++; break; case 'b': b[1] ++; break; case 'c': b[2] ++; break; case 'd': b[3] ++; break; 23 default : b[4] ++; } } for(i =0; i<5; i++) System.out.print(b[i]+\ System.out.println(); } } ¡¾ÔËÐнá¹û¡¿ 4 3 2 2 3 6£®public class X6_3_6 { public static void main(String[] args) { int a[] = {76,83,54,62,40,75,90,92,77,84}; int b[] = {60,70,90,101}; int c[]=new int[4],i; for (i=0; i while (a[i] >= b[j] ) j ++; c[j] ++; } for (i=0; i<4; i++) System.out.print(c[i]+\ System.out.println(); } ¡¾ÔËÐнá¹û¡¿ 2 1 5 2 ËÄ¡¢±à³ÌÌâ 1£®ÓÐÒ»¸öÊýÁУ¬ËüµÄµÚÒ»ÏîΪ0£¬µÚ¶þÏîΪ1£¬ÒÔºóÿһÏî¶¼ÊÇËüµÄǰÁ½ÏîÖ®ºÍ£¬ÊÔ²úÉú¸ÃÊýÁеÄǰ20Ï²¢°´ÄæÐòÏÔʾ³öÀ´¡£ ¡¾±à³Ì·ÖÎö¡¿±¾ÀýÓÉÓÚÉæ¼°µ½20ÏîÊý¾ÝµÄ´æ´¢£¬Òò´Ë¿ÉÒÔÀûÓÃÊý×éÀ´ÊµÏÖ¡£ÓÉÓÚÊýÁеĸ÷ÏîÖ®¼ä´æÔÚÒ»¶¨µÄ¹ØÏµ£¬¿ÉÒÔÀûÓÃǰÁ½ÏîÀ´¼ÆËãºóÃæÏî¡£ ¡¾²Î¿¼´ð°¸¡¿ public class X6_4_1 { public static void main(String[] args) { int[] a = new int[20]; a[0]=0; a[1]=1; int i; for(i=2;i<20;i++){ a[i]=a[i-1]+a[i-2]; // ÇóÆäÓà18Ïî } for(i=0;i<20;i++){ // ÿһÐÐÏÔʾ5¸öÔªËØ if(i%5 == 0) System.out.println(); System.out.print(a[i]+\ } 24