Compilare: user.cpp: In function ‘int main()’: user.cpp:106:17: warning: variable ‘x11’ set but not used [-Wunused-but-set-variable] int x11 = e[j][1]; ^ user.cpp:107:17: warning: variable ‘x22’ set but not used [-Wunused-but-set-variable] int x22 = e[j][2]; ^ user.cpp:108:17: warning: variable ‘x33’ set but not used [-Wunused-but-set-variable] int x33 = e[j][3]; ^ user.cpp:86:13: warning: unused variable ‘x1’ [-Wunused-variable] int x1 = e[i][1]; ^ user.cpp:87:13: warning: unused variable ‘x2’ [-Wunused-variable] int x2 = e[i][2]; ^ user.cpp:88:13: warning: unused variable ‘x3’ [-Wunused-variable] int x3 = e[i][3]; ^ user.cpp:32:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("go2.in", "r", stdin); ^ user.cpp:33:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("go2.out", "w", stdout); ^ user.cpp:35:28: 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:39:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s + 1); ^ /tmp/ccIyhFaR.o: In function `main': user.cpp:(.text.startup+0x90): warning: the `gets' function is dangerous and should not be used.