Compilare: user.cpp: In function ‘void plusEgalVector(std::vector<int>&, std::vector<int>&)’: user.cpp:25:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; i < v1.size(); i++) { ^ user.cpp:31:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; i < v2.size(); i++) { ^ user.cpp: In function ‘void minusEgalVector(std::vector<int>&, std::vector<int>&)’: user.cpp:43:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = v2.size(); i < v1.size(); i++) { ^ user.cpp:46:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < v1.size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:61:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mult.out", "w", stdout); ^ user.cpp:62:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mult.in", "r", stdin); ^ user.cpp:65:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &K); ^ user.cpp:68:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i]); ^