C++ 简单文件输入输出代码记录

#include<iostream>
#include<fstream>
int main()
{
	using namespace std;
	char automobile[50];
	int year;
	double a_price;
	double d_price;

	ofstream outFile;
	outFile.open("c.txt");
	cout << "Enter the make and model of automobile:";
	cin.getline(automobile,50);
	cout << "Enter the model year";
	cin >> year;
	cout << "Enter the original asking price: ";
	cin >> a_price;
	d_price = 0.913*a_price;

	cout << fixed;
	cout.precision(2);
	cout.setf(ios_base::showpoint);
	cout << "Make and model: " << automobile << endl;
	cout << "year: " << year << endl;
	cout << "Was asking $" << a_price << endl;
	cout << "Now asking $" << d_price << endl;

	outFile << fixed;
	outFile.precision(2);
	outFile.setf(ios_base::showpoint);
	outFile << "Make and model: " << automobile << endl;
	outFile << "Year: " << year << endl;
	outFile << "Was asking $" << a_price << endl;
	outFile << "Now asking $" << d_price << endl;
	outFile.close();

	return 0;
}


#include<iostream>
#include<fstream>
#include<cstdlib>
const int SIZE = 60;
int main()
{
	using namespace std;
	char filename[SIZE];
	ifstream inFile;
	cout << "Enter  name of data file: ";
	cin.getline(filename,SIZE);
	inFile.open(filename);
	if (!inFile.is_open())
	{
		cout << "Could not open the file " << filename << endl;
		cout << "Program terminating.\n";
		exit(EXIT_FAILURE);
	}
	double value;
	double sum = 0.0;
	int count = 0;

	inFile >> value;
	while (inFile.good())
	{
		++count;
		sum += value;
		inFile >> value;
	}
	if (inFile.eof())
		cout << "Enf of file reached.\n";
	else if (inFile.fail())
		cout << "Input terminated by data mismatch.\n";
	else
		cout << "Input terminated for unknown reason.\n";

	if (count == 0)
		cout << "No data processed.\n";
	else
	{
		cout << "Items reak: " << count << endl;
		cout << "Sum: " << sum << endl;
		cout << "Average: " << sum / count << endl;
	}

		return 0;
}