The file data.txt has the following contents: first second third What are the values of x, y, and z in the program below? #include <fstream> #include <string> #include <iostream> int main(void) { std::ifstream f; f.open("data.txt", std::ios::in | std::ios::out); std::string x, y, z; f >> x >> y >> z; } A.x: "first ", : "second ", : "third "yz B.x: "first second third", : "", : ""yz C.x: "first", : "second", : "third"yz D.x: "third", : "second", : "first"yz答案选哪个

C. x: "first", y: "second", z: "third"。

因为在程序中首先打开名为“data.txt”的文件，然后用std::string类型的变量x，y和z读取文件中的三个字符串。在读取文件时，std::ifstream对象会自动将文件内容分割成单个字符串，并将其存储在变量x，y和z中，因此x包含第一个字符串“first”，y包含第二个字符串“second”，z包含第三个字符串“third”。

相关问题

Write a C++ program that implements flipping the contents of each line of a string in a text file and outputs the flipped result to another text file. Both the input file name and output file name are specified by the user. Example: Suppose the input file input.txt has the following contents: Hello, world! Welcome to C++! After executing the program, the output file output.txt should contain the following contents: !dlrow ,olleH !++C ot emocleW Tip: You can use the getline() function to read the string from the input file line by line, then use the reverse() function to flip the string, and finally write the flipped string to the output file.

Sure, here's a C++ program that implements flipping the contents of each line of a string in a text file and outputs the flipped result to another text file:

#include <iostream>
#include <fstream>
#include <string>
#include <algorithm>

using namespace std;

int main() {
    string inputFileName, outputFileName;
    cout << "Enter input file name: ";
    cin >> inputFileName;
    cout << "Enter output file name: ";
    cin >> outputFileName;

    ifstream inputFile(inputFileName);
    if (!inputFile.is_open()) {
        cout << "Error opening input file." << endl;
        return 1;
    }

    ofstream outputFile(outputFileName);
    if (!outputFile.is_open()) {
        cout << "Error opening output file." << endl;
        return 1;
    }

    string line;
    while (getline(inputFile, line)) {
        reverse(line.begin(), line.end());
        outputFile << line << endl;
    }

    inputFile.close();
    outputFile.close();

    cout << "File contents flipped successfully." << endl;
    return 0;
}

In this program, we first ask the user to enter the input file name and output file name. We then open the input file using ifstream and check if the file was opened successfully. Similarly, we open the output file using ofstream and check if the file was opened successfully.

We then read the input file line by line using getline(), and flip each line using the reverse() function from the algorithm library. Finally, we write the flipped line to the output file using ofstream.

After all the lines have been flipped and written to the output file, we close both the input and output files and display a success message.

Note that this program assumes that the input file contains valid text data and that the output file can be created or overwritten without any issues.

associate.py: error: the following arguments are required: first_file, second_file

这个错误提示是因为你在运行 associate.py 脚本时，没有按照脚本的要求正确提供所需要的参数。

你需要在运行脚本时，指定两个参数，即第一个文件和第二个文件。可以像下面这样来运行脚本：

python associate.py first_file.txt second_file.txt

其中 `first_file.txt` 和 `second_file.txt` 分别是你想要比较的两个文件名。请确保这两个文件都存在，并且在运行脚本时提供了正确的文件路径。