Question

我正在从文本文件中读取值并将其作为字符串打印到屏幕。我们的想法是读取每个单独的字符串并将它们打印到屏幕上，并在其旁边打印读取的字符串的运行平均值。我有我的字符串浮动声明

int main()
{

string inputfile, intstring;
float counter;
counter = 0;
float average;
average = 0;
float stringconv = stof(intstring);

cout << "Enter the name of a file to open\n";
cin >> inputfile;

ifstream inFile;
inFile.open(inputfile.c_str());

以后再计算平均值

while (!inFile.eof())
{
    getline(inFile, intstring, ' '); 
    cout << intstring <<","<<average<< endl;
    //increments counter to keep average output correct
    counter = counter +1;
    //goes to next line at each space encountered in text file
    average = (counter + stringconv) /2;
}

我已经把这包括在内，万一我的问题就在那里。谁能告诉我如何正确宣布我的转换？这是一个完整的版本，编译

#include <math.h>
#include <iostream>
#include <string>
#include <fstream>
using namespace std;

int main()
{

string inputfile, intstring;
float counter;
counter = 0;
float average;
average = 0;
float dividor;
dividor = 1;

cout << "Enter the name of a file to open\n";
cin >> inputfile;

ifstream inFile;
inFile.open(inputfile.c_str());

if (!inFile)
{
    cout << "Error opening file " << inputfile << endl;
    char stopchar;
    cin >> stopchar;
    return -1;
}

while (!inFile.eof())
{
//goes to next line at each space encountered in text file
getline(inFile, intstring, ' '); 
cout << intstring <<","<<average<< endl;
float stringconv;
stringconv = stof(intstring);

average = (counter + stringconv)/dividor ;
dividor = dividor +1;

//increments counter to keep average output correct



}

inFile.close();
char stopchar;
cin >> stopchar;
}

Answer 1

下面：

string inputfile, intstring;
...
float stringconv = stof(intstring);

你不能这样做。我的意思是，你可以，但它并没有做你认为它做的事情。您认为自己正在创建宏或功能，以便您可以更改intstring，然后stringconv会自动更改。但你实际上做的是将未初始化的字符串转换为整数一次，并且永远不会再次更改它。您必须在读取循环内进行转换。

编辑：如果您不需要使用stof()，那么您可以使用流输入运算符来节省很多麻烦：

float number;
inFile >> number;       // this is the basic form
while(inFile >> number) // this is how to do it as a loop
  ...

Answer 2

在C ++中，float stringconv = stof(intstring);赢得了Verilog中的assign自动转换功能。

每次需要转换时，请致电stof()。

试试这个：

while (!inFile.eof())
{
    getline(inFile, intstring, ' '); 
    cout << intstring <<","<<average<< endl;
    //increments counter to keep average output correct
    counter = counter +1;
    //goes to next line at each space encountered in text file
    stringconv = stof(intstring); // add this here
    average = (counter + stringconv) /2;
}

错误的stof（）声明

2 个答案: