Question

大家晚上好，我试图得到一个向量向量，实质上是存储值的表，其中第二列使用第一列中的数字来计算它，但是，它不起作用。我希望它存储我的值，例如：

    T   R
0 | 20 [R1]
1 | 30 [R2]
2 | 40 [R3]
3 | 50 [R4]
4 | 60 [R5]
[Continues until hits last number]
The numbers along the left side are the rows like Stuff[0][T] = 20, etc

So T would be vector<double>Temp and R would be vector<double>Resistance and 
they are both contained in vector<vector<double> >Stuff.

因此，R向量将使用T的值来计算电阻。

int main ()                                                                                         
{

    double InitTemp,FinTemp,TempIncr;
    vector <vector <double> > Stuff;

    cout << "What is the range of temperatures being tested?(Initial Final) ";
    cin >> InitTemp >> FinTemp;
    cout << "How much would you like each temperature to increment? ";
    cin >> TempIncr;

    for(int i = 0; i < 2; i++)
    {
        vector <double> Temp;
        vector<double> Resistance;
        if(i == 0)
        {

            for (int j = InitTemp; j <= FinTemp; j+=TempIncr)
                Temp.push_back(j);
            Stuff.push_back(Temp);
        }

        if(i == 1)
        {

            double R=0;
            for(int k = 0; k < Temp.size();k++)
            {
                R = Temp[k]+1;
                Resistance.push_back(R);
            }
            Stuff.push_back(Resistance);
        }

    for (int i = 0; i< Stuff.size(); i++)
    {
        for(int j = 0; j < Stuff[i].size(); j++)
            cout << Stuff[i][j] << " ";
        cout << endl;
    }

这部分程序将放在另一个更大的程序中，该程序使用一个函数来计算电阻，但是我仍然需要使用Temp来执行此操作，这就是为什么我只将temp加1作为占位符。我的输出看起来像这样：

What is the range of temperatures being tested?(Initial Final) 20 200
How much would you like each temperature to increment? 10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
Press any key to continue . . .

它甚至没有输出第二个向量。请帮助我理解

Answer 1

选择std::vector中的std::pair<double, double>。然后，您的代码将变得更加简单。第一个double是Temperature，第二个Resistance。根据我在您的代码中看到的，Resistance仅被添加到Temperature中。在这种情况下，以下代码应该起作用：

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

int main()
{
    double InitTemp, FinTemp, TempIncr;
    vector <pair<double, double > > Stuff;

    cout << "What is the range of temperatures being tested?(Initial Final) ";
    cin >> InitTemp >> FinTemp;
    cout << "How much would you like each temperature to increment? ";
    cin >> TempIncr;

    for (int j = InitTemp; j <= FinTemp; j += TempIncr)             
        Stuff.emplace_back(j, j+1);

    for (int i = 0; i < Stuff.size(); i++)
    {
        cout << Stuff[i].first << ", " << Stuff[i].second << endl;
    }
}

如何使2D向量中的每个向量不同？

1 个答案: