// Project20161020.cpp : 定義控制檯應用程式的入口點。
//

#include "stdafx.h"
#include<iostream>
#include<exception>
#include<fstream>
#include<string>
#include<vector>
using namespace std;
/**
丟擲並捕獲多個異常
*/
void readIntegerFile(const string& fileName, vector<int> &dest)
{
	ifstream istr;
	int temp;
	istr.open(fileName);
	if (istr.fail())
	{
		throw runtime_error("Unable to open the file");
	}
	while (istr >> temp)
	{
		dest.push_back(temp);
	}
	if (!istr.eof()){
		//We did not reach the end-of-file
		//This means that some error occurred while reading the file
		//Throw an exception
		//檔案結尾是非數字 則丟擲
		throw runtime_error("Error reading the file.");
	}
}
int main()
{
	vector<int> myInts;
	const string& fileName = "C:/Users/Administrator/Desktop/IntegerFile.txt";
	try {
		readIntegerFile(fileName, myInts);
	}
	catch (const exception e) {
		cerr << e.what() << endl;
		return 1;
	}
	for (const auto element : myInts)
	{
		cout << element << " ";
	}
	cout << endl;
    return 0;
}
 

#include "stdafx.h"
#include<iostream>
#include<stdexcept>
#include<fstream>
#include<string>
#include<vector>
using namespace std;
/**
   也可以讓readIntegerFile()丟擲兩種不同型別的異常。以下是實現
   如果不能開啟檔案，則丟擲invalid_argument類異常物件，如果無法讀取整數，就丟擲runtime_error類物件。
   invalid_argument和runtime_error都是定義在<stdexcept>標頭檔案中的類
*/
void readIntegerFile(const string& fileName, vector<int> &dest)
{
	ifstream istr;
	int temp;
	istr.open(fileName);
	if (istr.fail())
	{
		throw invalid_argument("Unable to open the file");
	}
	while (istr >> temp)
	{
		dest.push_back(temp);
	}
	if (!istr.eof()) {
		//We did not reach the end-of-file
		//This means that some error occurred while reading the file
		//Throw an exception
		//檔案結尾是非數字 則丟擲
		throw runtime_error("Error reading the file.");
	}
}
int main()
{
	vector<int> myInts;
	const string& fileName = "C:/Users/Administrator/Desktop/IntegerFile.txt";
	//main()函式可以用兩個catch語句捕獲invalid_argument和runtime_error
	try {
		readIntegerFile(fileName, myInts);
	}
	catch (const invalid_argument& e) {
		cerr << e.what() << endl;
		return 1;
	}
	catch (const runtime_error& e) {
		cerr << e.what() << endl;
		return 1;
	}
	for (const auto&element : myInts) 
	{
		cout << element << " ";
	}
	cout << endl;
	return 0;
}