从另一个文件读取时写入文件

Can we do both in a function, while using the elements of input file, can we write the results in output file same time?

我们可以在一个函数中同时使用输入文件的元素，我们可以同时在输出文件中写入结果吗？

inside of while statement is true?

在while语句里面是真的吗？

void solve(string inputFileName, string outputFileName)
{
//declaring variables
string filename = inputFileName;

//Open a stream for the input file
ifstream inputFile;
inputFile.open( filename.c_str(), ios_base::in );

//open a stream for output file
outputfile = outputFileName;
ofstream outputFile;
outputFile.open(outputfile.c_str(), ios_base::out);

while(!inputFile.eof())
{
    inputFile >> number;    //Read an integer from the file stream
    outputFile << number*100 << "\n"
    // do something

}

//close the input file stream
inputFile.close();

//close output file stream
outputFile.close();
}

2 个解决方案

#1

while(!inputFile.eof())

doesn't work very well, because it tests if the previous operation failed, not if the next one will be successful.

不能很好地工作，因为它测试前一个操作是否失败，而不是下一个操作是否成功。

Instead try

相反，试试

while(inputFile >> number)
{
    outputFile << number*100 << "\n"
    // do something

}

where you test each input operation for success and terminate the loop when the read fails.

在哪里测试每个输入操作是否成功，并在读取失败时终止循环。

#2

You can, the input and output stream are independent from each other, so mixing them together in statements has no combined effect.

您可以，输入和输出流彼此独立，因此在语句中将它们混合在一起没有综合效果。

#1

while(!inputFile.eof())