Eroare de compilare: user.cpp: In function ‘void mergesort(int*, unsigned int, unsigned int, unsigned int)’: user.cpp:16:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(b[i]<=a[j]) ^ user.cpp:5:5: warning: unused variable ‘u’ [-Wunused-variable] int u[100]; ^ user.cpp: In function ‘int main()’: user.cpp:44:1: error: ‘ifstream’ was not declared in this scope ofstream g("algsort.out"); ^ user.cpp:44:1: 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/istream:38, from /usr/local/include/c++/4.8.0/fstream:38, from user.cpp:2: /usr/local/include/c++/4.8.0/iosfwd:157:34: note: ‘std::ifstream’ typedef basic_ifstream<char> ifstream; ^ user.cpp:44:10: error: expected ‘;’ before ‘f’ ofstream g("algsort.out"); ^ user.cpp:45:1: error: ‘ofstream’ was not declared in this scope f>>n; ^ user.cpp:45:1: 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/istream:38, from /usr/local/include/c++/4.8.0/fstream:38, from user.cpp:2: /usr/local/include/c++/4.8.0/iosfwd:160:34: note: ‘std::ofstream’ typedef basic_ofstream<char> ofstream; ^ user.cpp:45:10: error: expected ‘;’ before ‘g’ f>>n; ^ user.cpp:46:1: error: ‘f’ was not declared in this scope for(i=1;i<=n;i++) ^ user.cpp:51:2: error: ‘g’ was not declared in this scope f.close();g.close(); ^ user.cpp:52:11: error: ‘g’ was not declared in this scope return 0; ^