Compilare: user.cpp: In function ‘void afis(std::vector<int>)’: user.cpp:78:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<a.size();i++){ ^ user.cpp: In function ‘std::vector<int> join(std::vector<int>&, std::vector<int>&)’: user.cpp:88:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ((i < left.size()) && (j < right.size())) { ^ user.cpp:88:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ((i < left.size()) && (j < right.size())) { ^ user.cpp:97:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < left.size()) { ^ user.cpp:101:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < right.size()) { ^ user.cpp: In function ‘int main()’: user.cpp:162:34: 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:164:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d", &N); ^ user.cpp:166:51: 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:172:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d", &M); ^ user.cpp:174:49: 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); ^