/in/foo.c: In function 'main':
/in/foo.c:6:1: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
 for(i=2;i<=x-1;i++)
 ^~~
/in/foo.c:9:2: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
  if(i<x)
  ^~
/in/foo.c:4:10: warning: unused variable 'a' [-Wunused-variable]
  int x,i,a=0;
          ^