Compilare: user.cpp: In function ‘int main()’: user.cpp:44:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxsubsum.in", "r", stdin); ^ user.cpp:45:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxsubsum.out", "w", stdout); ^ user.cpp: In function ‘long long int solve(int*, int, int&)’: user.cpp:37:15: warning: ‘end’ may be used uninitialized in this function [-Wmaybe-uninitialized] len = end - beg + 1; ^ user.cpp:37:15: warning: ‘beg’ may be used uninitialized in this function [-Wmaybe-uninitialized] user.cpp: In function ‘int main()’: user.cpp:37:15: warning: ‘beg’ may be used uninitialized in this function [-Wmaybe-uninitialized] user.cpp:18:9: note: ‘beg’ was declared here int beg, end, idx = 1; ^ user.cpp:37:15: warning: ‘end’ may be used uninitialized in this function [-Wmaybe-uninitialized] len = end - beg + 1; ^ user.cpp:18:14: note: ‘end’ was declared here int beg, end, idx = 1; ^ user.cpp:37:15: warning: ‘beg’ may be used uninitialized in this function [-Wmaybe-uninitialized] len = end - beg + 1; ^ user.cpp:18:9: note: ‘beg’ was declared here int beg, end, idx = 1; ^ user.cpp:37:15: warning: ‘end’ may be used uninitialized in this function [-Wmaybe-uninitialized] len = end - beg + 1; ^ user.cpp:18:14: note: ‘end’ was declared here int beg, end, idx = 1; ^