C + + writes output to file/read data from File

Include the header file first

#include <fstream>

Output to File

Ofstream Fout; declares an output stream object

Fout.open ("output.txt"); Open (if not created) a file

(or directly below with Ofstream Fout ("output.txt"))

Fout.close (); Close File

1Template <classT>2 voidArray<t>:: Showlist () {3Ofstream Fout ("output.txt");4      for(inti =0; i < size; ++i) {5Fout << List[i] <<" ";6cout << List[i] <<" ";7     }8Fout <<Endl;9 fout.close ();Tencout <<Endl; One}

Input from File

Ifstream fin ("input.txt");

1Template <classT>2 voidArray<t>:: Setlist () {3Ifstream Fin ("Input.txt");4      for(inti =0; i < size; ++i) {5 T N;6Fin >>N;7List[i] =N;8     }9}

Attention:

If you want to read a whole line into a char array, we can't use the ">>" operator, because the space (whitespace character) between each word aborts the file's reading.
Want to include the whole sentence, there is a way to read the whole line, it is getline ().
such as: fin.getline (sentence, 100);

C + + writes output to file/read data from File