Compilare: user.cpp: In function ‘int main()’: user.cpp:37:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (poz > c[x].size() ) ^ user.cpp:52:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (poz > l[x].size()) ^ user.cpp:9:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qmatrix.in", "r", stdin); ^ user.cpp:10:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qmatrix.out", "w", stdout); ^ user.cpp:13:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &n, &x, &y, &q); ^ user.cpp:30:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("\n"); ^ user.cpp:33:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c %d %d\n", &ch, &poz, &x); ^