【问题标题】:Return a vector or array from a function in C++从 C++ 中的函数返回向量或数组
【发布时间】:2016-05-06 05:10:14
【问题描述】:

我想创建一个程序,根据用户输入创建 N 矩阵,但我需要返回向量(或数组)值,然后将它们发送到函数,然后再次通过返回向量来获取。

例如:

vector<int> createMatrix(rows, cols){
    for(int x = 0; x < rows; x++){
        for(int y = 0; y < cols; y++){
            cout << "Please, input the values for the row " << x << " and col " << y << endl;
            vector<int> Matrix(...)values;
            cin >> (...);
        }
    }
return Matrix; //here is the point
}

vector<int> mathOperations(operation, matrixA, matrixB){
    (...)
    return vector<int> resultMatrix;
}

int main(int argc, char *argv[]){
    int nMatrix, nRows, nCols;
    cout << "Please, answer how many matrix would you like do be created?" << endl;
    cin >> nMatrix;
    cout << "Thank you, and how many rows your matrix will have?" << endl;
    cin >> nRows;
    cout << "Thank you again, and how many cols?" << endl;
    cin >> nCols;
    cout << "Okey, creating " << nMatrix << " nMatrix for you!" << endl;

    for(int n = 0; n < nMatrix; n++){
        cout << "Please, insert the values for the matrix no" << n+1 << endl;
        vector<int> myMatrix[n] = createMatrix(nRows, nCols);
    }

    /* the rest of my code with functions to print values, create a new vectors by math operations between given arguments
    */

return 0;
}

最好的方法是什么?

【问题讨论】:

    标签: c++ arrays function matrix vector


    【解决方案1】:

    如果您正在寻找一种使用vector 构造二维结构的方法,请使用以下内容:

    #include <vector>
    #include <iostream>
    
    using std::vector;
    using std::cout;
    using std::cin;
    
    typedef vector<vector<int> > matrix_t;
    
    matrix_t createMatrix(int rows, int cols){
      matrix_t Matrix(rows, vector<int>(cols));
    
      for(int x = 0; x < rows; x++){
        for(int y = 0; y < cols; y++){
          cout << "Please, input the values for the row "
            << x << " and col " << y << std::endl;
          cin >> Matrix[x][y];
        }
      }
      return Matrix;
    }
    
    int main(int argc, char const* argv[])
    {
      matrix_t M(createMatrix(2, 2));
    
      for (int i = 0; i < 2; i++) {
        for (int j = 0; j < 2; j++) {
          cout << M[i][j] << std::endl;
        }
    
      }
    
      return 0;
    }
    

    【讨论】:

    • @juanchopanza,是的,reserve 不会改变矢量的大小,所以我需要resize。修复了答案
    • 好的,我现在将移除 cmets。顺便提一句。您可以通过像这样初始化向量来跳过调整大小循环:matrix_t Matrix(rows, vector&lt;int&gt;(cols));。请参阅我对this old question 的回复。
    • @juanchopanza,啊,确实,我们可以传递一个向量作为初始项值。
    猜你喜欢
    • 1970-01-01
    • 1970-01-01
    • 2022-07-18
    • 2023-03-09
    • 1970-01-01
    • 1970-01-01
    • 2017-01-13
    • 1970-01-01
    • 2013-10-01
    相关资源
    最近更新 更多