Compilare: user.cpp: In function ‘int main()’: user.cpp:52:6: warning: variable ‘last1’ set but not used [-Wunused-but-set-variable] int last1, last2; ^ user.cpp:52:13: warning: variable ‘last2’ set but not used [-Wunused-but-set-variable] int last1, last2; ^ user.cpp:46:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("piete.in", "r", stdin); ^ user.cpp:47:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("piete.out", "w", stdout); ^ user.cpp:48:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &n, &m, &s, &f); ^ user.cpp:51:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &Cost[i][j]); ^