/in/foo.c: In function 'main':
/in/foo.c:17:17: error: called object 'count' is not a function or function pointer
     int count = count(str, c);
                 ^~~~~
/in/foo.c:17:9: note: declared here
     int count = count(str, c);
         ^~~~~
/in/foo.c:18:12: warning: too many arguments for format [-Wformat-extra-args]
     printf("两个字符串中小写字母的个数\n", c, count, str);
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~