Compilare: user.cpp: In function ‘int main()’: user.cpp:69:26: warning: unused variable ‘k’ [-Wunused-variable] int nrgroups = 0, j, k; ^ user.cpp:35:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("litere2.in", "r", stdin); ^ user.cpp:37:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(a); ^ /tmp/ccepagsQ.o: In function `main': user.cpp:(.text.startup+0x4b): warning: the `gets' function is dangerous and should not be used.