/in/foo.c: In function 'main':
/in/foo.c:12:17: error: 'n' undeclared (first use in this function)
     scanf("%d",&n);
                 ^
/in/foo.c:12:17: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:34:13: error: 'j' undeclared (first use in this function)
         for(j=i+1;j<n;j++)
             ^
/in/foo.c:42:12: error: array subscript is not an integer
         oil[minj][1]=oil[i][1];
            ^
/in/foo.c:57:14: warning: format '%d' expects argument of type 'int', but argument 2 has type 'double' [-Wformat=]
     printf("%d\n",sum);
              ^
/in/foo.c:71:14: warning: format '%d' expects argument of type 'int', but argument 2 has type 'double' [-Wformat=]
     printf("%d\n",sum);
              ^
/in/foo.c:9:12: warning: variable 'minj' set but not used [-Wunused-but-set-variable]
  float min,minj;
            ^~~~
/in/foo.c:7:11: warning: unused variable 'jn' [-Wunused-variable]
     int i,jn;
           ^~