作为矢量参数的数组的列

column of an array as a vector argument

本文关键字：数组 参数      更新时间：2023-10-16

我试图传递一个数组的列向量参数，但我不知道如何做到这一点。我使用的是"矢量"库。我要贴一个例子来说明我想要什么:

#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;
}

它不工作:(有人能帮我吗?

Thanks in advance

我认为你可以这样写程序

#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;
}

如果你想计算第一列的和，你可以这样做:

#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;
}
相关文章：