Compilare: user.cpp: In function ‘int main()’: user.cpp:76:25: warning: unused variable ‘a’ [-Wunused-variable] int x,y,a; ^ user.cpp:85:25: warning: unused variable ‘a’ [-Wunused-variable] int x,y,a; ^ user.cpp:43:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unicat.in", "r", stdin); ^ user.cpp:44:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unicat.out", "w", stdout); ^ user.cpp:46:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s\n%s",v1+1,v2+1); ^