Compilare: user.cpp: In function ‘int main()’: user.cpp:66:6: warning: unused variable ‘t’ [-Wunused-variable] int t; ^ user.cpp:34:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ratina.in", "r", stdin); ^ user.cpp:35:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ratina.out", "w", stdout); ^ user.cpp:37:26: 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:46:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(A + len); ^ user.cpp:68:10: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(A); ^ user.cpp:38:39: warning: ‘lastlen’ may be used uninitialized in this function [-Wmaybe-uninitialized] int pos = 0, len = 0, i, maxlen = 0, lastlen; ^ In file included from /usr/include/stdio.h:934:0, from user.cpp:3: In function ‘char* gets(char*)’, inlined from ‘int main()’ at user.cpp:46:16: /usr/include/i386-linux-gnu/bits/stdio2.h:230:28: warning: call to ‘__gets_warn’ declared with attribute warning: please use fgets or getline instead, gets can't specify buffer size [enabled by default] return __gets_warn (__str); ^ /tmp/cc3wd45d.o: In function `main': user.cpp:(.text.startup+0xff): warning: the `gets' function is dangerous and should not be used. user.cpp:(.text.startup+0x391): warning: the `gets' function is dangerous and should not be used.