Compilare: user.cpp: In function ‘int main()’: user.cpp:73:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v.size(); ++i) cnt[v[i]-'0']++; ^ user.cpp:96:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < z.size(); ++i) printf("%c", z[i]); ^ user.cpp:65:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bignumber.in", "r", stdin); ^ user.cpp:66:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bignumber.out", "w", stdout); ^ user.cpp:67:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &n, &x); ^ user.cpp:70:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &c); ^