Compilare: user.c:3: warning: second argument of ‘main’ should be ‘char **’ user.c: In function ‘main’: user.c:6: warning: passing argument 2 of ‘freopen’ from incompatible pointer type /usr/include/stdio.h:255: note: expected ‘const char * __restrict__’ but argument is of type ‘struct _IO_FILE *’ user.c:6: warning: passing argument 3 of ‘freopen’ from incompatible pointer type /usr/include/stdio.h:255: note: expected ‘struct FILE * __restrict__’ but argument is of type ‘char *’ user.c:7: warning: passing argument 2 of ‘freopen’ from incompatible pointer type /usr/include/stdio.h:255: note: expected ‘const char * __restrict__’ but argument is of type ‘struct _IO_FILE *’ user.c:7: warning: passing argument 3 of ‘freopen’ from incompatible pointer type /usr/include/stdio.h:255: note: expected ‘struct FILE * __restrict__’ but argument is of type ‘char *’ user.c:5: warning: unused variable ‘sum’ user.c:6: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:7: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:9: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:11: warning: control reaches end of non-void function