Compilare: main.cpp: In function 'void write()': main.cpp:103:13: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] i=n; Ans[n]=NULL; ^~~~ main.cpp: In function 'void read_and_insert()': main.cpp:13:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("strigat.in","r",stdin); ^ main.cpp:14:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ main.cpp:17:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%s%d",W,&f); ^ main.cpp: In function 'void write()': main.cpp:100:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("strigat.out","w",stdout); ^