Compilare: main.cpp: In function 'int main()': main.cpp:22:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<strlen(a);i+=2) ~^~~~~~~~~~ main.cpp:12:10: warning: unused variable 'q' [-Wunused-variable] char q; ^ main.cpp:13:28: warning: unused variable 'nrap' [-Wunused-variable] int i, k=1, maxk=1, p, nrap=0, s=0, x; ^~~~ main.cpp:13:41: warning: unused variable 'x' [-Wunused-variable] int i, k=1, maxk=1, p, nrap=0, s=0, x; ^ main.cpp:14:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("charlie.in","r",stdin); ^ main.cpp:15:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("charlie.out","w",stdout); ^