Compilare: user.cpp: In function ‘int main()’: user.cpp:9:33: warning: unused variable ‘a’ [-Wunused-variable] int n, k, i, l1=0, l2=0, m, a, sum, tr; ^ user.cpp:7:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("transport.in","r", stdin); ^ user.cpp:8:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("transport.out","w",stdout); ^