所以我一直在寻找如何将我的字符串向量转换为双向量的答案。每个人似乎都认为
ss.str(std::string());
ss.str();
ss.str("");
应该有效。虽然我已经尝试过了，但这是不行的。
我在使用stringstream之前已经完成了这个，但这次流中的缓存并没有清除，我的输出只是一堆连续连接的数字。
例如，我输入7 9 58 33.我得到：
7 79 7958 795833
这是在一个循环中，我假设是复杂的事情，但我不认为这应该是一个问题。这是代码。我所指的函数调用是real2double。问题出在函数的最后一个for循环中。
#include <iostream>
#include <String>
#include <vector>
#include <sstream>
using namespace std;
#ifndef Comp_Num
class Comp_Num
{
private:
std::vector <double> real;
std::vector <double> imag;
double real_in, imag_in;
string operation;
public:
Comp_Num();
Comp_Num(std::vector <string> complex_nums);
static std::vector <string> get_input();
static std::vector <string> get_real(std::vector <string> complexnum1);
static std::vector <string> get_imag(std::vector <string> complexnum2);
static void display(std::vector <string> display1);
static void display2(std::vector <double> display3);
static std::vector <string> set_compnum(std::vector <string> set_num);
static std::vector <string> comp2real(std::vector <string> c2r);
static vector <double> real2double (std::vector<string> r2d);
~Comp_Num();
/*
double Comp_Num::operator+ (double add_num);
double Comp_Num::operator- (double sub_num);
double Comp_Num::operator* (double mul_num);
double Comp_Num::operator/ (double div_num);
*/
};
#endif !Comp_Num
Comp_Num::Comp_Num(std::vector <string> complex_nums)
{
/*
std::vector <string> input_fin;
input_fin = Comp_Num::get_input();
Comp_Num::display(real1);
std::cout<<"What operation would you like to perform\n";
std::cout<<"You can choose from addition, subtraction, multiplication, or division.\n";
std::cin>>operation>>"\n";
*/
};
std::vector <string> Comp_Num::set_compnum(std::vector <string> set_num)
{
std::vector<string>comp1=Comp_Num::get_real(set_num);
std::vector <string>comp2= Comp_Num::get_imag(set_num);
std::vector <string>cmp2rl_fin = Comp_Num::comp2real(comp2);
std::vector <double>finale = Comp_Num::real2double(cmp2rl_fin);
Comp_Num::display(comp1);
Comp_Num::display(comp2);
Comp_Num::display(cmp2rl_fin);
Comp_Num::display2(finale);
system("pause");
return(comp2);
};
std::vector <string> get_input()
{
std::string usr_input, input1;
std::vector <string> complex;
std::cout<<"Enter the real or imaginary numbers you would like to perform your operation on.\n";
std::cout<<"Enter abc for your last value.\n";
std::getline(std::cin, usr_input);
std::istringstream input(usr_input);
while(input >> input1)
{
if(input1 == "abc")
break;
complex.push_back(input1);
}
std::cout<<'\n';
return (complex);
};
std::vector <string> Comp_Num::get_imag(std::vector <string> complexnum2)
{
std::vector <string> imag1;
for(unsigned int i = 0; i < complexnum2.size(); ++i)
{
std::string str2 = "";
std::vector<char> char1(complexnum2[i].begin(), complexnum2[i].end());
for(unsigned int r = 0; r < char1.size(); ++r)
{
if(char1[r] >= '0' && char1[r] <= '9' || char1[r] == '-' || char1[r] == '.' || char1[r] == 'i')
{
str2 += char1[r];
if(char1[r] == 'i')
{
imag1.push_back(str2);
continue;
}
}
}
}
return(imag1);
};
std::vector <string> Comp_Num::get_real(std::vector <string> complexnum1)
{
std::vector <string> real1;
for(unsigned int i = 0; i < complexnum1.size(); ++i)
{
std::string str2 = "";
std::vector<char> char1(complexnum1[i].begin(), complexnum1[i].end());
for(unsigned int r = 0; r < char1.size(); ++r)
{
if(char1[r] >= '0' && char1[r] <= '9' || char1[r] == '-' || char1[r] == '.' || char1[r] == 'i')
{
str2 += char1[r];
if(char1[r] == 'i')
{
str2="";
break;
}
}
}
real1.push_back(str2);
}
return(real1);
};
void Comp_Num::display (std::vector <string> display1)
{
unsigned int i = 0;
while (i < display1.size())
{
std::cout<<display1[i]<<" ";
i++;
}
std::cout<<std::endl;
};
void Comp_Num::display2 (std::vector <double> display3)
{
unsigned int i = 0;
while (i < display3.size())
{
std::cout<<display3[i]<<" ";
i++;
}
std::cout<<std::endl;
};
std::vector <string> Comp_Num::comp2real(std::vector <string> c2r)
{
std::vector <string> real2;
for(unsigned int i = 0; i < c2r.size(); ++i)
{
std::string str2 = "";
std::vector<char> char1(c2r[i].begin(), c2r[i].end());
for(unsigned int r = 0; r < char1.size(); ++r)
{
if(char1[r] >= '0' && char1[r] <= '9' || char1[r] == '-' || char1[r] == '.')
{
str2 += char1[r];
}
}
real2.push_back(str2);
}
return(real2);
}
std::vector<double> Comp_Num::real2double (std::vector<string> r2d)
{
double y;
std::vector<double> final_r2d;
std::string str, str2;
std::vector<string>str3;
for(unsigned int i = 0; i < r2d.size(); ++i)
{
std::vector<char> ch(r2d[i].begin(), r2d[i].end());
for(unsigned int r = 0; r < ch.size(); ++r)
{
if(ch[r] >= '0' && ch[r] <= '9' || ch[r] == '-' || ch[r] == '.')
{
str2 += ch[r];
}
}
str3.push_back(str2);
}
for(unsigned int r = 0; r < str3.size(); r++)
{
// std::string open = "";
// istringstream to_double(open);
str = str3[r];
std::istringstream to_double(str);
while(to_double >> y)
{
final_r2d.push_back(y);
to_double.str(std::string());
}
}
return(final_r2d);
};
答案 0 :(得分：1)
问题出在real2double的第一个循环中，你继续追加变量
str2 += ch[r];
您必须将声明移动到循环中：
for(unsigned int i = 0; i < r2d.size(); ++i)
{
std::string str2;
<强>后来 废除代码重复：
template <class T>
static void display(std::vector <T> display);
template <class T>
void Comp_Num::display (std::vector <T> dis) {
for( typename std::vector<T>::iterator it = dis.begin() ; it != dis.end(); ++it ){
std::cout << *it << " ";
}
std::cout<<std::endl;
}
尽可能避免循环：
std::vector<double> Comp_Num::real2double (std::vector<string> r2d) {
for( std::vector<string>::iterator it = r2d.begin() ; it != r2d.end(); ++it ){
int iPos = (*it).find_first_not_of( "0123456789-." );
double y;
std::istringstream( (*it).substr( 0, iPos ) ) >> y;
final_r2d.push_back( y );
}
return final_r2d;
}