Eroare de compilare: user.cpp: In function ‘void back(int, int)’: user.cpp:89:10: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if (sum<=nr) ^ user.cpp: At global scope: user.cpp:101:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main() ^ user.cpp: In function ‘int main()’: user.cpp:105:4: error: ‘ifstream’ was not declared in this scope ifstream f("cifru4.in"); ^ user.cpp:105:4: note: suggested alternative: In file included from /usr/local/include/c++/4.8.0/ios:38:0, from /usr/local/include/c++/4.8.0/ostream:38, from /usr/local/include/c++/4.8.0/iostream:39, from user.cpp:1: /usr/local/include/c++/4.8.0/iosfwd:157:34: note: ‘std::ifstream’ typedef basic_ifstream<char> ifstream; ^ user.cpp:105:13: error: expected ‘;’ before ‘f’ ifstream f("cifru4.in"); ^ user.cpp:112:4: error: ‘f’ was not declared in this scope f>>n>>p>>k; ^ user.cpp:142:4: error: ‘ofstream’ was not declared in this scope ofstream g("cifru4.out"); ^ user.cpp:142:4: note: suggested alternative: In file included from /usr/local/include/c++/4.8.0/ios:38:0, from /usr/local/include/c++/4.8.0/ostream:38, from /usr/local/include/c++/4.8.0/iostream:39, from user.cpp:1: /usr/local/include/c++/4.8.0/iosfwd:160:34: note: ‘std::ofstream’ typedef basic_ofstream<char> ofstream; ^ user.cpp:142:13: error: expected ‘;’ before ‘g’ ofstream g("cifru4.out"); ^ user.cpp:143:4: error: ‘g’ was not declared in this scope g<<sol; ^