/in/foo.c:2:23: error: unknown type name 'sum'
 int gethe(int m,int n,sum s);
                       ^~~
/in/foo.c: In function 'main':
/in/foo.c:12:2: error: unknown type name 'sum'
  sum s[100];sum temp;
  ^~~
/in/foo.c:12:2: note: use 'struct' keyword to refer to the type
/in/foo.c:12:13: error: unknown type name 'sum'
  sum s[100];sum temp;
             ^~~
/in/foo.c:12:13: note: use 'struct' keyword to refer to the type
/in/foo.c:15:1: warning: implicit declaration of function 'scaf' [-Wimplicit-function-declaration]
 scaf("%d",&s[i].h);
 ^~~~
/in/foo.c:15:16: error: request for member 'h' in something not a structure or union
 scaf("%d",&s[i].h);
                ^
/in/foo.c:16:17: error: request for member 'k' in something not a structure or union
 scanf("%d",&s[i].k);
                 ^
/in/foo.c:20:12: error: request for member 'h' in something not a structure or union
   { if(s[j].h<s[j+1].h)
            ^
/in/foo.c:20:21: error: request for member 'h' in something not a structure or union
   { if(s[j].h<s[j+1].h)
                     ^
/in/foo.c:28:12: error: request for member 'h' in something not a structure or union
  {if(2*s[i].h<=gethe(i,n,s))
            ^
/in/foo.c:28:16: warning: implicit declaration of function 'gethe' [-Wimplicit-function-declaration]
  {if(2*s[i].h<=gethe(i,n,s))
                ^~~~~
/in/foo.c:34:11: error: request for member 'k' in something not a structure or union
   g=g+s[i].k;
           ^
/in/foo.c: At top level:
/in/foo.c:38:23: error: unknown type name 'sum'
 int gethe(int m,int n,sum s)
                       ^~~