C++ 从TXT文件中一行一行的读取数据并且保存到数组中

ゞ浴缸里的玫瑰 2023-02-23 07:48 7阅读 0赞

## C++ 从TXT文件中一行一行的读取数据并且保存到数组中 ##

这里使用了vector数组，以及new 动态数组，组成二维数组。

**fscanf(fp,"%lf", &rowArray\[i\])**：获取文件中数据，并将其赋值给 rowArray\[i\]，"%lf" 为双精度

**fscanf函数详解，参考：**[https://blog.csdn.net/zhuiqiuzhuoyue583/article/details/107151385][https_blog.csdn.net_zhuiqiuzhuoyue583_article_details_107151385]

#include <fstream>
    #include <string>
    #include <iostream>
    #include <vector>
    using namespace std;
    
    // 功能：将filename 中的数据（共cols列）读取到_vector中，_vector可视为二维数组
    int read_scanf(const string &filename, const int &cols, vector<double *> &_vector)
    {
    	FILE *fp = fopen(filename.c_str(), "r");
    	bool flag = true;
    	int i = 0;
    	if (!fp) 
    	{ 
    		cout << "File open error!\n"; 
    		return 0; 
    	}
    
    	while (flag)
    	{
    		double *rowArray = new double[cols]; //new一个double类型的动态数组
    
    		for (i = 0; i < cols; i++) //读取数据，存在_vector[cols]中
    		{
    			if (EOF == fscanf(fp,"%lf", &rowArray[i]))
    			{ 
    				flag = false; 
    				break; 
    			}
    			//输出rowArray存入的数据
    			//cout << rowArray[0] << " " << rowArray[1] << " " << rowArray[2] << " " << rowArray[3] << endl;
    		}
    		if (cols == i) //将txt文本文件中的一行数据存入rowArray中，并将rowArray存入vector中
    			_vector.push_back(rowArray);
    	}
    	fclose(fp);
    	return 1;
    }
    int  main()
    {
            string file ="test.txt";
    	//txt文件中有4列
    	int columns = 4;
    	vector<double *> output_vector;
    	if (!read_scanf(file, columns, output_vector))
    	{
    		return 0;
    	}
    		
    	//output_vector可视为二维数组;输出数组元素：
    	int rows = output_vector.size();
    	for (int i = 0; i < rows; i++)
    	{
    		for (int j = 0; j < columns; j++) 
    		{ 
    			cout << output_vector[i][j] << " "; 
    		}
    		cout << endl;
    	}
    
    	system("pause");
    	return 0;
    }

test.txt中的数据为：

8 0 3 2
    8 0 3 25

输出结果为：

![20200705222444756.png][]

**fscanf函数详解，参考：**[https://blog.csdn.net/zhuiqiuzhuoyue583/article/details/107151385][https_blog.csdn.net_zhuiqiuzhuoyue583_article_details_107151385]

[https_blog.csdn.net_zhuiqiuzhuoyue583_article_details_107151385]: https://blog.csdn.net/zhuiqiuzhuoyue583/article/details/107151385
[20200705222444756.png]: https://img-blog.csdnimg.cn/20200705222444756.png