Question

我试图将一个数组的列作为向量参数传递，但我不知道该怎么做。我正在使用＆＃34; vector＆＃34;图书馆。我将发布一个例子来澄清我想要的东西：

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

//function for get the sum of all the elements of a vector H
double suma(vector<double> H) {
    double Sum = 0.0;
    for (int i = 0; i < H.size(); i++) {
        Sum += H[i];
    }
    return Sum;
}

int main() {
    vector<vector<double> > phi;
    phi.resize(10, vector<double> (2,1.0));
    cout << suma(phi[][1]) << endl;
}

它不起作用:(任何人都可以帮助我吗？

提前致谢

Answer 1

我认为你可以用这种方式编写你的程序

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

double suma(vector<vector<double> >& H) {
    double Sum = 0.0;
    for (size_t i = 0; i < H.size(); ++i) {
        // probably you need to write one more inner loop to do 
        // something with each vector.This is not very clear with your question
    }
    return Sum;
}


int main() {
   vector<vector<double> > phi(10,vector<double> (2,1.0));
    cout << suma(phi) << endl;
}

Answer 2

如果要计算第一列的总和，可以这样做：

#include <iostream>
#include <vector>

using namespace std;

//function for get the sum of all the elements of a vector H
double suma(vector<double> H) {

    double Sum = 0.0;
    for (int i = 0; i < H.size(); i++) {
        Sum += H[i];
    }

    return Sum;
}

int main() {

    vector<vector<double> > phi;

    phi.resize(10, vector<double> (2,1.0));
    //if by 0th column you mean 0th vector do this:
    cout << suma(phi[0]) << endl;

    //if by 0th column you mean every 0th element of each vector do this:
    vector<double> temp;
    for(int i=0; i<phi.size(); i++)
    {
        temp.push_back(phi[i][0]);
    }
    cout << suma(temp) << endl;
}

数组的列作为向量参数

2 个答案: