/in/fileReverse.c: In function 'main':
/in/fileReverse.c:19:19: error: initialization makes integer from pointer without a cast [-Werror=int-conversion]
     char filename=argv[1];
                   ^~~~
/in/fileReverse.c:24:15: error: passing argument 1 of 'fopen' makes pointer from integer without a cast [-Werror=int-conversion]
     fin=fopen(filename,"r");
               ^~~~~~~~
In file included from /in/fileReverse.c:2:0:
/usr/include/stdio.h:232:14: note: expected 'const char * restrict' but argument is of type 'char'
 extern FILE *fopen (const char *__restrict __filename,
              ^~~~~
cc1: all warnings being treated as errors