Compilare: main.cpp: In function 'int main()': main.cpp:61:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < q[i].size() ; ++j) ans[q[i][j].second] = s[q[i][j].first]; ~~^~~~~~~~~~~~~ main.cpp: In function 'char GetChar()': main.cpp:10:38: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff,1,BUFF_SIZE,stdin); ^ main.cpp: In function 'int main()': main.cpp:42:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("inversari.in", "r", stdin); ^ main.cpp:43:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("inversari.out", "w", stdout); ^