foo.c: In function 'main':
foo.c:15:7: error: 'fp' undeclared (first use in this function)
foo.c:15:7: note: each undeclared identifier is reported only once for each function it appears in
foo.c:16:1: warning: implicit declaration of function 'strlen' [-Wimplicit-function-declaration]
foo.c:16:3: warning: incompatible implicit declaration of built-in function 'strlen' [enabled by default]
foo.c:18:1: warning: array subscript has type 'char' [-Wchar-subscripts]
foo.c:26:8: error: 'fp1' undeclared (first use in this function)
foo.c:12:7: warning: unused variable 'n' [-Wunused-variable]