Compilare: main.cpp: In function 'int main()': main.cpp:29:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int it = 0; ok == 0 && it < vec[mm].size(); it++) { ~~~^~~~~~~~~~~~~~~~ main.cpp:30:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(vec[mm][it] == nr) { main.cpp:53:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int it = 0; it < vec[mm].size(); it++) { ~~~^~~~~~~~~~~~~~~~ main.cpp:54:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(vec[mm][it] == nr) { main.cpp:63:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int it = 0; it < vec[mm].size(); it++) { ~~~^~~~~~~~~~~~~~~~ main.cpp:64:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(vec[mm][it] == nr) { main.cpp:14:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("abc2.in", "r", stdin); ^ main.cpp:15:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("abc2.out", "w", stdout); ^ main.cpp:16:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s); ^