Compilare: main.cpp: In function 'int main()': main.cpp:44:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x < v[c].size() && v[c][x] == a){ ~~^~~~~~~~~~~~~ main.cpp:30:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("marbles.in","r",stdin); ^ main.cpp:31:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("marbles.out","w",stdout); ^ main.cpp:33:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:35:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &pos, &c); ^ main.cpp:40:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &t, &a, &b); ^