如何在c ++中声明文件？ [英] How to declare a file in c++ ?

问题描述

我已经创建了一个名为（student.txt）的文件，我将以下信息放在文件中





Will Smith 99

Sarah Johnson 100

Tim Howard 70

Francesco Totti 95
Michael Jackson 92



我想要求用户输入文件名，一旦输入文件名，我想通过读取数据来显示平均分数文件。



注意：文件中的每一行都包含学生的名字，姓氏和考试成绩。


这是我到目前为止所做的，这只能显示文件里面的内容

请帮我声明文件名并显示平均分数学生

I have already created a file called ( student.txt) and i put the following information inside the file


Will Smith 99
Sarah Johnson 100
Tim Howard 70
Francesco Totti 95
Michael Jackson 92

I want to ask the user to enter the file name,once they enter the file name, I want to displays the average score by reading the data from the file.

Note : Each line in the file contains the first name, last name, and test score of a student.

Here's what i did so far and this could only display what inside the file
Please help me to declare the file name and to display the average score of a student

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

using namespace std;
int main() {
	string studentFile;

	ifstream file("student.txt");
	if (file.is_open()) {
		while (getline(file,studentFile))
		{
			cout << line << '\n';

		}
		file.close();

	}

推荐答案

您应该使用ifstream进行输入。



阅读： http://www.cplusplus.com/doc/tutorial/files/ [ ^ ]

和： http://www.cplusplus.com/reference/fstream/ifstream/open/ [ ^ ]



然后：

You should be using ifstream for input.

Read this: http://www.cplusplus.com/doc/tutorial/files/[^]
and:http://www.cplusplus.com/reference/fstream/ifstream/open/[^]

Then:

ifstream studentfile;
string studentfilename;

cout << "Please enter the student file name = ";
cin >> studentfilename;
studentfile.open(studentfilename);

open（）中的std :: string参数仅在C11中合法。

std::string argument in open() is legal in C11 only.

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