Compilare: user.cpp: In function ‘int main()’: user.cpp:82:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,n,m,k,z; ^ user.cpp:82:17: warning: unused variable ‘k’ [-Wunused-variable] int i,j,n,m,k,z; ^ user.cpp:82:19: warning: unused variable ‘z’ [-Wunused-variable] int i,j,n,m,k,z; ^ user.cpp:85:36: 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:86:39: 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:88:24: 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:88:33: 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:90:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/cccVrJWs.o: In function `main': user.cpp:(.text.startup+0x74): warning: the `gets' function is dangerous and should not be used.