demo_4_file_txt_3_b.cpp

对于一个初涉VC＋＋的人来书

//****************************************************
// 显示职工工资文件,并将该文件拷贝到另一个文件中.
//****************************************************

# include <fstream.h> //该头文件包含iostream.h
# include <stdlib.h>

const char *old_file="Salary.txt";
const char *new_file="Salary_Copy.txt";

int main()
{
	ifstream input_file;  //输入文件流
	ofstream output_file; //输出文件流
//	fstream input_file,output_file; //输入输出文件流
	char ch;

	//注意: 若声明输入输出文件流fstream对象,则:
	//input_file.open(old_file); //Error!
    //Error: 'open' function does not take 1 parameters
	input_file.open(old_file);
//	input_file.open(old_file,ios::in);
//	input_file.open(old_file,ios::in|ios::nocreate);
	if(!input_file)
	{
		cerr<<"Open file error!"<<endl;
		exit(1);
	}

	//注意: 若声明输入输出文件流fstream对象,则:
	//output_file.open(new_file); //Error!
    //Error: 'open' function does not take 1 parameters
	output_file.open(new_file);
//	output_file.open(new_file,ios::out);
	if(!output_file)
	{
		cerr<<"Open file error!"<<endl;
		exit(1);
	}

	while(input_file.get(ch))
	{
		cout<<ch;
		output_file.put(ch);
	}
	cout<<endl;

	output_file.close();
	input_file.close();
	
	return 0;
}