" 'yc' can not be used as a function"错误C++

" 'yc' can not be used as a function" error in C++

本文关键字：function C++ as 错误 not yc can be used      更新时间：2023-10-16

我正在使用C 计算NACA 4数字翼型坐标。在此代码中，我使用Armadillo库的Linspace功能将X分为线性间隔点。当我使用for循环来计算每个 x的值的 yc的值时，我得到错误" yc"无法用作函数。感谢您的帮助。

#include<iostream>
#include<armadillo>
#include<vector>
using namespace std;
using namespace arma;
int main()
{
    float a[3];
    float c;
    int gp = 100;
    cout << "Please Enter NACA 4 digits" << endl;
    cout << "Please Enter 1st digit" << endl;
    cin >> a[0] ;
    cout << "Please Enter 2nd digit" << endl;
    cin >> a[1] ;
    cout << "Please Enter last 2 digits" << endl;
    cin >> a[2] ;
    cout << "Please Enter Chord Length" << endl;
    cin >> c;
    float m=(a[0]*c)/100;
    float p=(a[1]*c)/10;
    float t=(a[2]*c)/100;
    cout << m << endl;
    cout << p << endl;
    cout << t << endl;
    vec x = linspace<vec>(0, c, gp);
    float yc;
    for(int i=0;i<gp;++i)
        {
            if (x(i) = 0 && x(i) <= p){
            yc(i) = (m/(p*p))*((2*p*(x(i)))-(x(i)*x(i)));
        }
            if (x(i) > p && x(i) <= c) {
            yc(i) =(m/((1-p)*(1-p)))*((1-(2*p))+(2*p*x(i))-(x(i)*x(i)));
        }
        }
    cout<< yc <<endl;
return 0;
}

yc是单个浮点。

编译器将symbol( )视为函数调用。这就是错误的含义。

也许创建YC

的数组 
float yc[gp];

并使用

yc[i] = ....

突出显示-yc[gp]可能不起作用，所以

float * yc = new float[gp];

，在main()

的末尾 
delete []yc;

这是一个示例，如何将std::vector用于此类任务。

vector<float> v(size);的声明用float的size值填充向量，这些值均设置为0.0，这是float的标准值：

#include <iostream>
#include <vector>
using namespace std;
// demonstrates how a vector is used as a better variadic array:
void vector_usage(int size){
    // initializing a vector with size 0 values
    std::vector<float> v(size);
    // fill in some (not very meaningful) values
    for(int i=0; i<size; ++i) {
        if ((4 <= i) && (i < 8))
            v[i] = 15.0/i;
    }
    // inspect the result on console:
    for (auto e: v) {
        cout << e << " ";
    }
    cout << endl;
    // hopefully having learned something ;)
}
int main() {
    vector_usage(12);
    return 0;
}

请参阅IDEONE.com上的实时演示...

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