如何使用C ++从txt文件读取n个值 [英] How to read n values from txt file using C++
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问题描述
我有以下c ++代码,可用来从.txt文件中读取值
I have the following c++ code by which I am reading values from .txt file
请帮助我改善代码,以便我不仅可以读取.txt中的14个值,还可以读取n个值
Could you please help me to improve the code such that I can read not only 14 values but n values from the .txt
//reading from text file
static std::vector<double> vec;
double a[14]; //values got read from txt file
int i = 0;
void readDATA()
{
double value;
std::ifstream myFile;
myFile.open("filename.txt", std::ios::app);
if (myFile.is_open())
{
std::cout << "File is open." << std::endl;
while (myFile >> value)
{
vec.push_back(value);
std::cout << "value is " << value << std::endl;
a[i] = value;
std::cout << "a" << i << "=" << a[i] << std::endl;
i = i + 1;
}
myFile.close();
}
else
std::cout << "Unable to open the file";
}
.txt文件看起来像
the .txt file looks like
0 0 40 45 15
0 1 40 -45 10
0 0 180 90 15
推荐答案
vec.push_back(value);
这里,值已经添加到 vec
中,您无需再次将它们添加到 a
中.您只需输入 vec [n]
即可访问这些值.例如,
Here, values are already added to vec
, you don't need to add them to a
again. You can just access those values by typing vec[n]
. For example,
std::cout<<vec[2]; //40
std::cout<<vec[4]; //15
您可以将任意多的元素推回向量,因此您实际上不需要声明其他数组或双精度数.
And you can push back as many elements as you like to vectors, so you really don't need to declare another array or doubles.
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