Compilare: user.cpp: In function ‘int main()’: user.cpp:19:9: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(a[i]); ^~~~ In file included from /usr/include/c++/6/cstdio:42:0, from /usr/include/x86_64-linux-gnu/c++/6/32/bits/stdc++.h:46, from user.cpp:1: /usr/include/stdio.h:638:14: note: declared here extern char *gets (char *__s) __wur __attribute_deprecated__; ^~~~ user.cpp:19:18: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(a[i]); ^ In file included from /usr/include/c++/6/cstdio:42:0, from /usr/include/x86_64-linux-gnu/c++/6/32/bits/stdc++.h:46, from user.cpp:1: /usr/include/stdio.h:638:14: note: declared here extern char *gets (char *__s) __wur __attribute_deprecated__; ^~~~ user.cpp:14:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("karma.in","r",stdin); ^ user.cpp:15:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("karma.out","w",stdout); ^ user.cpp:17:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n",&n,&m); ^ user.cpp:19:19: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(a[i]); ^ /tmp/ccPmbWHz.o: In function `main': user.cpp:(.text.startup+0x78): warning: the `gets' function is dangerous and should not be used.