Compilare: user.cpp: In function ‘int main()’: user.cpp:100:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("puzzle2.in", "r", stdin); ^ user.cpp:101:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("puzzle2.out", "w", stdout); ^ user.cpp:104:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:107:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &xx, &yy); ^ user.cpp: In function ‘int vecin(int)’: user.cpp:33:12: warning: ‘sol’ may be used uninitialized in this function [-Wmaybe-uninitialized] return sol; ^ user.cpp: In function ‘void doit(int, int)’: user.cpp:69:19: warning: ‘sol’ may be used uninitialized in this function [-Wmaybe-uninitialized] while (deg[nod] != 1) { ^