Compilare: user.cpp: In function ‘int main()’: user.cpp:81:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,n,m,x,y,k,z; ^ user.cpp:81:21: warning: unused variable ‘k’ [-Wunused-variable] int i,j,n,m,x,y,k,z; ^ user.cpp:84:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("invazia.in","r",stdin); ^ user.cpp:85:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("invazia.out","w", stdout); ^ user.cpp:87:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); gets(s); ^ user.cpp:87:33: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); gets(s); ^ user.cpp:89:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/ccz4jGle.o: In function `main': user.cpp:(.text.startup+0x76): warning: the `gets' function is dangerous and should not be used.