Compilare: main.cpp: In function 'void add_hash(int)': main.cpp:13:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while( i < v[code].size() && x != v[code][i] ) ~~^~~~~~~~~~~~~~~~ main.cpp:15:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( i == v[code].size() ) ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'bool search_hash(int)': main.cpp:21:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while( i < v[code].size() && x != v[code][i] ) ~~^~~~~~~~~~~~~~~~ main.cpp:23:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return i < v[code].size(); ~~^~~~~~~~~~~~~~~~ main.cpp: In function 'void erase_hash(int)': main.cpp:28:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while( i < v[code].size() && x != v[code][i] ) ~~^~~~~~~~~~~~~~~~ main.cpp:30:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( i < v[code].size() ) ~~^~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:40:26: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf( fin, "%d", &n ); ^ main.cpp:42:35: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf( fin, "%d%d", &op, &x ); ^