/in/foo.c:11:14: error: unknown type name 'student'
 int jiangjin(student n)
              ^~~~~~~
/in/foo.c: In function 'main':
/in/foo.c:31:2: error: unknown type name 'student'
  student shujus [n];
  ^~~~~~~
/in/foo.c:31:2: note: use 'struct' keyword to refer to the type
/in/foo.c:32:2: error: unknown type name 'student'
  student max_jj;
  ^~~~~~~
/in/foo.c:32:2: note: use 'struct' keyword to refer to the type
/in/foo.c:35:39: error: request for member 'name' in something not a structure or union
   scanf("%s %d %d %c %c %d",&shujus[i].name,&shujus[i].cj,&shujus[i].bjcj,&shujus[i].bg,&shujus[i].xb,&shujus[i].lw);
                                       ^
/in/foo.c:35:55: error: request for member 'cj' in something not a structure or union
   scanf("%s %d %d %c %c %d",&shujus[i].name,&shujus[i].cj,&shujus[i].bjcj,&shujus[i].bg,&shujus[i].xb,&shujus[i].lw);
                                                       ^
/in/foo.c:35:69: error: request for member 'bjcj' in something not a structure or union
   scanf("%s %d %d %c %c %d",&shujus[i].name,&shujus[i].cj,&shujus[i].bjcj,&shujus[i].bg,&shujus[i].xb,&shujus[i].lw);
                                                                     ^
/in/foo.c:35:85: error: request for member 'bg' in something not a structure or union
   scanf("%s %d %d %c %c %d",&shujus[i].name,&shujus[i].cj,&shujus[i].bjcj,&shujus[i].bg,&shujus[i].xb,&shujus[i].lw);
                                                                                     ^
/in/foo.c:35:99: error: request for member 'xb' in something not a structure or union
   scanf("%s %d %d %c %c %d",&shujus[i].name,&shujus[i].cj,&shujus[i].bjcj,&shujus[i].bg,&shujus[i].xb,&shujus[i].lw);
                                                                                                   ^
/in/foo.c:35:113: error: request for member 'lw' in something not a structure or union
   scanf("%s %d %d %c %c %d",&shujus[i].name,&shujus[i].cj,&shujus[i].bjcj,&shujus[i].bg,&shujus[i].xb,&shujus[i].lw);
                                                                                                                 ^
/in/foo.c:36:5: warning: implicit declaration of function 'jiangjin' [-Wimplicit-function-declaration]
   m=jiangjin(shujus[i]);
     ^~~~~~~~
/in/foo.c:44:31: error: request for member 'name' in something not a structure or union
   printf("%s\n%d\n%d\n",max_jj.name,max,sSum);
                               ^
/in/foo.c:32:10: warning: variable 'max_jj' set but not used [-Wunused-but-set-variable]
  student max_jj;
          ^~~~~~
/in/foo.c:28:14: warning: unused variable 'jj' [-Wunused-variable]
  int n,i,max,jj,sSum=0,m;
              ^~