如何在c++中将计算分解为两个double和一个char

这对你有用吗？

string line = "1 operator 2";
stringstream ss(line);
double n1, n2;
string op;
ss >> n1;
ss >> op;
ss >> n2;

您需要解析字符串，或者将其标记化-将字符串拼接成单独的数据片段：

1. 分析字符串
2. 查找数据
3. 提取数据
4. 转换为x&y到双打
5. 根据运营商的说法。。。带有x和y(例如使用switch语句)

我提出的两种方法可以很容易地解决您的问题。你可以简单地找到"+"字符，然后得到该字符的左边是x，再到该字符的右边是y。然后将提取的字符串转换为双精度字符串。注意：只有当字符串中只有一个"x运算符y"时，这才是可以接受的。否则，您可能会获取比您想要的更多的。

还有另一种使用二叉树的方法。本质上，你可以用二进制树制作一个计算器，尽管它非常先进，我还不推荐你使用它。http://en.wikipedia.org/wiki/Binary_tree

使用第一个提出的解决方案的评论示例：

#include <iostream> //used for std::cout
#include <string>   //used for std::string
#include <sstream>  //used to convert a std::string to a double
#include <cctype>   //used for checking if a character is a digit(0-9.)
int main() 
{
//declare the source string to parse
std::string source = "2+6";
//output variables
//operator is a keyword, so just use op.
char op=' ';     
double x=0, y=0;
//parse source. iterate through each character starting at 0 (first character)
for(int i = 0; i < source.size(); i++) {
//check to see if its a character - ie if its not a number or . its an operator!
//(can be any *character* really - however must be only *1 character* long) and it must also not be a space.
if(!isdigit(source[i] || ' ')) {
//create the strings to put the copied data in
std::string xs, ys; //x and y strings
//get the left and right of the operator
//you could use a for loop, your choice.
//copy before the operator.
xs = source.substr(0, i);
//get the operator
op = source[i]; // by using the [i] - will just get a character from a string at [..]
//skip the operator by adding 1 - get the right hand side
ys = source.substr(i+1, source.size()-1);
//create the string stream used for converting the data to a double (its like std::cout and std::cin - uses the << and >>)
//use the stringstream xxs(..) <- to initialise the stringstream with our string above. 
std::stringstream xss(xs); //xss = xs string
std::stringstream yss(ys); //'   ' '  '
//now the string stream does the work for us. just feed the xss & yss string streams(which are our x & y strings) into the doubles using the >> operator, converting the data types.
xss >> x; //string TO double
yss >> y;
//don't want to search for any more characters now. finish up.
break;
}
}
std::cout << "x  = " << x  << std::endl;
std::cout << "op = " << op << std::endl;
std::cout << "y  = " << y  << std::endl;
std::system("pause");
return 0;
}

如果你只想看到裸代码，则无需注释：

#include <iostream>
#include <string>
#include <sstream> 
#include <cctype>  
int main()
{
std::string source = "2+6";
char op=' ';     
double x=0, y=0;
for(int i = 0; i < source.size(); i++) {
if(!isdigit(source[i]) || ' ') {
std::string xs, ys;
xs = source.substr(0, i);
op = source[i];
ys = source.substr(i+1, source.size()-1);
std::stringstream xss(xs);
std::stringstream yss(ys); 
xss >> x;
yss >> y;
break;
}
}
std::cout << "x  = " << x  << std::endl;
std::cout << "op = " << op << std::endl;
std::cout << "y  = " << y  << std::endl;
std::system("pause");

return 0;
}

这段代码不使用空格，也不使用空格。可以对其进行扩展，而不是查找单个字符作为运算符，而是查找1-3个字符。希望我能帮上忙：)