关于eclipse我有一个问题

1. /*这样是可以debug的*/
   
2. package q11_5;
   
3. 
   
4. import java.util.Arrays;
   
5. 
   
6. public class Q11_5{
   
7. 
   
8. public static int searchR(String[] strings,
   
9.                 String str,int first,int last){
   
10.         if(first>last){
    
11.                
    
12.                 return -1;
    
13.         }
    
14. 
    
15. int mid=(first+last)/2;
    
16. if(strings[mid].isEmpty()){
    
17. 
    
18. int left=mid-1;
    
19. int right=mid+1;
    
20. while(true){
    
21. if(left<first&&right>last){//through so many manipulations of BS,only '' left in this array
    
22. 
    
23.         return -1;
    
24. }else if(right<=last&&!strings[right].isEmpty()){
    
25. 
    
26.     mid=right;
    
27.     break;
    
28. }else if(left>=first&&!strings[left].isEmpty()){
    
29. 
    
30. mid=left;
    
31. break;
    
32. 
    
33. 
    
34. }
    
35. left--;
    
36. right++;
    
37. }
    
38. }
    
39. 
    
40. /*recursive*/
    
41. 
    
42. if(str.equals(strings[mid])){
    
43.         return mid;
    
44. }else if(strings[mid].compareTo(str)<0){//search thr right part
    
45. 
    
46. return searchR(strings,str,mid+1,last);
    
47. 
    
48. }else{
    
49.         return searchR(strings,str,first,mid-1);
    
50. }
    
51. }
    
52. 
    
53. 
    
54. public static int search(String[] strings,String str){
    
55. if(strings==null||str==null||str==""){
    
56. return -1;
    
57. 
    
58. }
    
59. 
    
60. return searchR(strings,str,0,strings.length-1);
    
61. }
    
62. 
    
63. 
    
64.         public static void main(String[] args) {
    
65.                 String[] strings={"Tong", "apple",
    
66.                                 "banana", "chaing", "click", "tom"};
    
67.                 System.out.println(search(strings,"tom"));
    
68.         }
    
69. }
    
70. 
    
71. /main函数改为int就不行了*/
    
72. package q11_5;
    
73. 
    
74. import java.util.Arrays;
    
75. 
    
76. public class Q11_5{
    
77. 
    
78. public static int searchR(String[] strings,
    
79.         String str,int first,int last){
    
80.     if(first>last){
    
81.         
    
82.         return -1;
    
83.     }
    
84. 
    
85. int mid=(first+last)/2;
    
86. if(strings[mid].isEmpty()){
    
87. 
    
88. int left=mid-1;
    
89. int right=mid+1;
    
90. while(true){
    
91. if(left<first&&right>last){//through so many manipulations of BS,only '' left in this array
    
92. 
    
93.     return -1;
    
94. }else if(right<=last&&!strings[right].isEmpty()){
    
95. 
    
96.     mid=right;
    
97.     break;
    
98. }else if(left>=first&&!strings[left].isEmpty()){
    
99. 
    
100. mid=left;
     
101. break;
     
102. 
     
103. 
     
104. }
     
105. left--;
     
106. right++;
     
107. }
     
108. }
     
109. 
     
110. /*recursive*/
     
111. 
     
112. if(str.equals(strings[mid])){
     
113.     return mid;
     
114. }else if(strings[mid].compareTo(str)<0){//search thr right part
     
115. 
     
116. return searchR(strings,str,mid+1,last);
     
117. 
     
118. }else{
     
119.     return searchR(strings,str,first,mid-1);
     
120. }
     
121. }
     
122. 
     
123. 
     
124. public static int search(String[] strings,String str){
     
125. if(strings==null||str==null||str==""){
     
126. return -1;
     
127. 
     
128. }
     
129. 
     
130. return searchR(strings,str,0,strings.length-1);
     
131. }
     
132. 
     
133. 
     
134.   public static int main(String[] args) {
     
135.         String[] strings={"Tong", "apple",
     
136.                 "banana", "chaing", "click", "tom"};
     
137.         return search(strings,"chiang");
     
138.     }
     
139. }
     
140. 
     

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会发现没有java application的选项