/in/foo.c: In function 'concat':
/in/foo.c:5:22: error: stray '\357' in program
   for(int i=1;b[i]!=0；i++)
                      ^
/in/foo.c:5:23: error: stray '\274' in program
   for(int i=1;b[i]!=0；i++)
                       ^
/in/foo.c:5:24: error: stray '\233' in program
   for(int i=1;b[i]!=0；i++)
                        ^
/in/foo.c:5:25: error: expected ';' before 'i'
   for(int i=1;b[i]!=0；i++)
                         ^
/in/foo.c:7:3: error: expected ';' before 'a'
   a[i+lena]=0;
   ^
/in/foo.c:8:22: error: stray '\357' in program
   for(int i=1;b[i]!=0；i++)
                      ^
/in/foo.c:8:23: error: stray '\274' in program
   for(int i=1;b[i]!=0；i++)
                       ^
/in/foo.c:8:24: error: stray '\233' in program
   for(int i=1;b[i]!=0；i++)
                        ^
/in/foo.c:8:25: error: expected ';' before 'i'
   for(int i=1;b[i]!=0；i++)
                         ^
/in/foo.c: In function 'main':
/in/foo.c:14:4: warning: 'gets' is deprecated [-Wdeprecated-declarations]
    gets(a);
    ^~~~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.c:15:4: warning: 'gets' is deprecated [-Wdeprecated-declarations]
    gets(b);
    ^~~~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~