Compilare: user.cpp: In function ‘std::vector<int> join(std::vector<int>&, std::vector<int>&)’: user.cpp:111:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ((i < left.size()) && (j < right.size())) { ^ user.cpp:111:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ((i < left.size()) && (j < right.size())) { ^ user.cpp:120:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < left.size()) { ^ user.cpp:124:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < right.size()) { ^ user.cpp: In function ‘int main()’: user.cpp:185:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zoo.out", "w", stdout); ^ user.cpp:187:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d", &N); ^ user.cpp:189:51: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d", &sorted[i].x, &sorted[i].y); ^ user.cpp:204:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d", &M); ^ user.cpp:206:49: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d %d %d", &x1, &y1, &x2, &y2); ^