[已解决]main函数的位置

南城转暖

main函数只能放在固定位置还是可以放在符合语法的任意位置。如果可以的话能不能举几个例子。ps：百度告诉我可以放在任意位置，但是我不知道怎么放！

最佳答案

月排行榜 / 总排行榜

人造人

2021-3-16 09:02:10

可以放在符合语法的任意位置，我比较喜欢放在最后面，这样可以省去声明函数

1. #include <stdio.h>
   
2. #include <stdlib.h>
   
3. #include <sys/stat.h>
   
4. #include <fcntl.h>
   
5. #include <unistd.h>
   
6. #include <sys/types.h>
   
7. #include <dirent.h>
   
8. #include <string.h>
   
9. 
   
10. size_t lines(const char *filename) {
    
11.     struct stat sb;
    
12.     if(lstat(filename, &sb) != 0) return 0;
    
13.     if(sb.st_size == 0) return 0;
    
14. 
    
15.     size_t count = 1;
    
16.     int fd = open(filename, O_RDONLY);
    
17.     char *buf = malloc(sb.st_size);
    
18.     read(fd, buf, sb.st_size);
    
19.     for(long i = 0; i < sb.st_size; ++i) {
    
20.         if(buf[i] == '\n') ++count;
    
21.     }
    
22.     free(buf);
    
23.     close(fd);
    
24.     return count;
    
25. }
    
26. 
    
27. const char *suffix(const char *filename) {
    
28.     return strrchr(filename, '.');
    
29. }
    
30. 
    
31. size_t count_lines(const char *path) {
    
32.     size_t count = 0;
    
33.     DIR *dirp = opendir(path);
    
34.     if(!dirp) return 0;
    
35. 
    
36.     struct dirent *de;
    
37.     char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    
38.     while((de = readdir(dirp))) {
    
39.         if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
    
40.         if(de->d_type == DT_DIR) {
    
41.             count += count_lines(de->d_name);
    
42.         }
    
43.         const char *s = suffix(de->d_name);
    
44.         if(!s || strcmp(s, ".c")) continue;
    
45.         count += lines(de->d_name);
    
46.     }
    
47.     chdir(cwd); free(cwd);
    
48.     closedir(dirp);
    
49.     return count;
    
50. }
    
51. 
    
52. int main(void) {
    
53.     printf("%lu\n", count_lines("../"));
    
54.     return 0;
    
55. }
    

复制代码

1. #include <stdio.h>
   
2. #include <stdlib.h>
   
3. #include <sys/stat.h>
   
4. #include <fcntl.h>
   
5. #include <unistd.h>
   
6. #include <sys/types.h>
   
7. #include <dirent.h>
   
8. #include <string.h>
   
9. 
   
10. size_t lines(const char *filename);
    
11. const char *suffix(const char *filename);
    
12. size_t count_lines(const char *path);
    
13. 
    
14. int main(void) {
    
15.     printf("%lu\n", count_lines("../"));
    
16.     return 0;
    
17. }
    
18. 
    
19. size_t lines(const char *filename) {
    
20.     struct stat sb;
    
21.     if(lstat(filename, &sb) != 0) return 0;
    
22.     if(sb.st_size == 0) return 0;
    
23. 
    
24.     size_t count = 1;
    
25.     int fd = open(filename, O_RDONLY);
    
26.     char *buf = malloc(sb.st_size);
    
27.     read(fd, buf, sb.st_size);
    
28.     for(long i = 0; i < sb.st_size; ++i) {
    
29.         if(buf[i] == '\n') ++count;
    
30.     }
    
31.     free(buf);
    
32.     close(fd);
    
33.     return count;
    
34. }
    
35. 
    
36. const char *suffix(const char *filename) {
    
37.     return strrchr(filename, '.');
    
38. }
    
39. 
    
40. size_t count_lines(const char *path) {
    
41.     size_t count = 0;
    
42.     DIR *dirp = opendir(path);
    
43.     if(!dirp) return 0;
    
44. 
    
45.     struct dirent *de;
    
46.     char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    
47.     while((de = readdir(dirp))) {
    
48.         if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
    
49.         if(de->d_type == DT_DIR) {
    
50.             count += count_lines(de->d_name);
    
51.         }
    
52.         const char *s = suffix(de->d_name);
    
53.         if(!s || strcmp(s, ".c")) continue;
    
54.         count += lines(de->d_name);
    
55.     }
    
56.     chdir(cwd); free(cwd);
    
57.     closedir(dirp);
    
58.     return count;
    
59. }
    

复制代码

1. #include <stdio.h>
   
2. #include <stdlib.h>
   
3. #include <sys/stat.h>
   
4. #include <fcntl.h>
   
5. #include <unistd.h>
   
6. #include <sys/types.h>
   
7. #include <dirent.h>
   
8. #include <string.h>
   
9. 
   
10. size_t lines(const char *filename) {
    
11.     struct stat sb;
    
12.     if(lstat(filename, &sb) != 0) return 0;
    
13.     if(sb.st_size == 0) return 0;
    
14. 
    
15.     size_t count = 1;
    
16.     int fd = open(filename, O_RDONLY);
    
17.     char *buf = malloc(sb.st_size);
    
18.     read(fd, buf, sb.st_size);
    
19.     for(long i = 0; i < sb.st_size; ++i) {
    
20.         if(buf[i] == '\n') ++count;
    
21.     }
    
22.     free(buf);
    
23.     close(fd);
    
24.     return count;
    
25. }
    
26. 
    
27. const char *suffix(const char *filename);
    
28. size_t count_lines(const char *path);
    
29. 
    
30. int main(void) {
    
31.     printf("%lu\n", count_lines("../"));
    
32.     return 0;
    
33. }
    
34. 
    
35. const char *suffix(const char *filename) {
    
36.     return strrchr(filename, '.');
    
37. }
    
38. 
    
39. size_t count_lines(const char *path) {
    
40.     size_t count = 0;
    
41.     DIR *dirp = opendir(path);
    
42.     if(!dirp) return 0;
    
43. 
    
44.     struct dirent *de;
    
45.     char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    
46.     while((de = readdir(dirp))) {
    
47.         if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
    
48.         if(de->d_type == DT_DIR) {
    
49.             count += count_lines(de->d_name);
    
50.         }
    
51.         const char *s = suffix(de->d_name);
    
52.         if(!s || strcmp(s, ".c")) continue;
    
53.         count += lines(de->d_name);
    
54.     }
    
55.     chdir(cwd); free(cwd);
    
56.     closedir(dirp);
    
57.     return count;
    
58. }
    

复制代码

跳转到最佳答案楼层

人造人

可以放在符合语法的任意位置，我比较喜欢放在最后面，这样可以省去声明函数

1. #include <stdio.h>
   
2. #include <stdlib.h>
   
3. #include <sys/stat.h>
   
4. #include <fcntl.h>
   
5. #include <unistd.h>
   
6. #include <sys/types.h>
   
7. #include <dirent.h>
   
8. #include <string.h>
   
9. 
   
10. size_t lines(const char *filename) {
    
11.     struct stat sb;
    
12.     if(lstat(filename, &sb) != 0) return 0;
    
13.     if(sb.st_size == 0) return 0;
    
14. 
    
15.     size_t count = 1;
    
16.     int fd = open(filename, O_RDONLY);
    
17.     char *buf = malloc(sb.st_size);
    
18.     read(fd, buf, sb.st_size);
    
19.     for(long i = 0; i < sb.st_size; ++i) {
    
20.         if(buf[i] == '\n') ++count;
    
21.     }
    
22.     free(buf);
    
23.     close(fd);
    
24.     return count;
    
25. }
    
26. 
    
27. const char *suffix(const char *filename) {
    
28.     return strrchr(filename, '.');
    
29. }
    
30. 
    
31. size_t count_lines(const char *path) {
    
32.     size_t count = 0;
    
33.     DIR *dirp = opendir(path);
    
34.     if(!dirp) return 0;
    
35. 
    
36.     struct dirent *de;
    
37.     char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    
38.     while((de = readdir(dirp))) {
    
39.         if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
    
40.         if(de->d_type == DT_DIR) {
    
41.             count += count_lines(de->d_name);
    
42.         }
    
43.         const char *s = suffix(de->d_name);
    
44.         if(!s || strcmp(s, ".c")) continue;
    
45.         count += lines(de->d_name);
    
46.     }
    
47.     chdir(cwd); free(cwd);
    
48.     closedir(dirp);
    
49.     return count;
    
50. }
    
51. 
    
52. int main(void) {
    
53.     printf("%lu\n", count_lines("../"));
    
54.     return 0;
    
55. }
    

复制代码

1. #include <stdio.h>
   
2. #include <stdlib.h>
   
3. #include <sys/stat.h>
   
4. #include <fcntl.h>
   
5. #include <unistd.h>
   
6. #include <sys/types.h>
   
7. #include <dirent.h>
   
8. #include <string.h>
   
9. 
   
10. size_t lines(const char *filename);
    
11. const char *suffix(const char *filename);
    
12. size_t count_lines(const char *path);
    
13. 
    
14. int main(void) {
    
15.     printf("%lu\n", count_lines("../"));
    
16.     return 0;
    
17. }
    
18. 
    
19. size_t lines(const char *filename) {
    
20.     struct stat sb;
    
21.     if(lstat(filename, &sb) != 0) return 0;
    
22.     if(sb.st_size == 0) return 0;
    
23. 
    
24.     size_t count = 1;
    
25.     int fd = open(filename, O_RDONLY);
    
26.     char *buf = malloc(sb.st_size);
    
27.     read(fd, buf, sb.st_size);
    
28.     for(long i = 0; i < sb.st_size; ++i) {
    
29.         if(buf[i] == '\n') ++count;
    
30.     }
    
31.     free(buf);
    
32.     close(fd);
    
33.     return count;
    
34. }
    
35. 
    
36. const char *suffix(const char *filename) {
    
37.     return strrchr(filename, '.');
    
38. }
    
39. 
    
40. size_t count_lines(const char *path) {
    
41.     size_t count = 0;
    
42.     DIR *dirp = opendir(path);
    
43.     if(!dirp) return 0;
    
44. 
    
45.     struct dirent *de;
    
46.     char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    
47.     while((de = readdir(dirp))) {
    
48.         if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
    
49.         if(de->d_type == DT_DIR) {
    
50.             count += count_lines(de->d_name);
    
51.         }
    
52.         const char *s = suffix(de->d_name);
    
53.         if(!s || strcmp(s, ".c")) continue;
    
54.         count += lines(de->d_name);
    
55.     }
    
56.     chdir(cwd); free(cwd);
    
57.     closedir(dirp);
    
58.     return count;
    
59. }
    

复制代码

1. #include <stdio.h>
   
2. #include <stdlib.h>
   
3. #include <sys/stat.h>
   
4. #include <fcntl.h>
   
5. #include <unistd.h>
   
6. #include <sys/types.h>
   
7. #include <dirent.h>
   
8. #include <string.h>
   
9. 
   
10. size_t lines(const char *filename) {
    
11.     struct stat sb;
    
12.     if(lstat(filename, &sb) != 0) return 0;
    
13.     if(sb.st_size == 0) return 0;
    
14. 
    
15.     size_t count = 1;
    
16.     int fd = open(filename, O_RDONLY);
    
17.     char *buf = malloc(sb.st_size);
    
18.     read(fd, buf, sb.st_size);
    
19.     for(long i = 0; i < sb.st_size; ++i) {
    
20.         if(buf[i] == '\n') ++count;
    
21.     }
    
22.     free(buf);
    
23.     close(fd);
    
24.     return count;
    
25. }
    
26. 
    
27. const char *suffix(const char *filename);
    
28. size_t count_lines(const char *path);
    
29. 
    
30. int main(void) {
    
31.     printf("%lu\n", count_lines("../"));
    
32.     return 0;
    
33. }
    
34. 
    
35. const char *suffix(const char *filename) {
    
36.     return strrchr(filename, '.');
    
37. }
    
38. 
    
39. size_t count_lines(const char *path) {
    
40.     size_t count = 0;
    
41.     DIR *dirp = opendir(path);
    
42.     if(!dirp) return 0;
    
43. 
    
44.     struct dirent *de;
    
45.     char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    
46.     while((de = readdir(dirp))) {
    
47.         if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
    
48.         if(de->d_type == DT_DIR) {
    
49.             count += count_lines(de->d_name);
    
50.         }
    
51.         const char *s = suffix(de->d_name);
    
52.         if(!s || strcmp(s, ".c")) continue;
    
53.         count += lines(de->d_name);
    
54.     }
    
55.     chdir(cwd); free(cwd);
    
56.     closedir(dirp);
    
57.     return count;
    
58. }
    

复制代码

chxchxkkk

意思就是你不用把main函数放在程序的第一行，在第任意行都可以

南城转暖

chxchxkkk 发表于 2021-3-16 09:23
意思就是你不用把main函数放在程序的第一行，在第任意行都可以

不可以放结尾吗？或者在其他位置吗

wp231957

人造人 发表于 2021-3-16 09:42
可以放在符合语法的任意位置，我比较喜欢放在最后面，这样可以省去声明函数

搭车问一下，您是否用过vscode+gcc
这个组合，我现在在vscode里无法编译

南城转暖

wp231957 发表于 2021-3-16 10:00
搭车问一下，您是否用过vscode+gcc
这个组合，我现在在vscode里无法编译

什么意思呢？如何无法编辑？

人造人

wp231957 发表于 2021-3-16 10:00
搭车问一下，您是否用过vscode+gcc
这个组合，我现在在vscode里无法编译

之前弄过，详细说明你的问题
qq: 1440332527