Compilare: user.cpp: In function ‘int main()’: user.cpp:53:18: warning: unused variable ‘a’ [-Wunused-variable] int k, i, t, a, b; ^ user.cpp:53:21: warning: unused variable ‘b’ [-Wunused-variable] int k, i, t, a, b; ^ user.cpp:56:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(inputFile.c_str(), "r", stdin); ^ user.cpp:57:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(outputFile.c_str(), "w", stdout); ^ user.cpp:60:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^