/in/foo.c: In function 'main':
/in/foo.c:10:3: warning: implicit declaration of function 'func' [-Wimplicit-function-declaration]
   func(str[i]);
   ^~~~
/in/foo.c: At top level:
/in/foo.c:14:5: error: conflicting types for 'func'
 int func(char x)
     ^~~~
/in/foo.c:15:1: note: an argument type that has a default promotion can't match an empty parameter name list declaration
 {
 ^
/in/foo.c:10:3: note: previous implicit declaration of 'func' was here
   func(str[i]);
   ^~~~
/in/foo.c: In function 'func':
/in/foo.c:22:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^