" “ yc”不能用作功能“ C ++中的错误 [英] " 'yc' can not be used as a function" error in C++

问题描述

我正在使用C ++计算NACA 4位机翼坐标。在这段代码中，我使用了犰狳库的linspace函数将x划分为线性间隔的点。当我使用for循环为每个 x 的值计算 yc 的值时，出现错误 yc不能用作功能。谢谢。

I am calculating NACA 4 digit airfoil coordinates using C++. In this code I used armadillo library's linspace function to divide x into linearly spaced points. When I use a for loop to calculate yc's value for each x's value I get error "yc" can not be used as function. Thanks for helping.

#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;
}

推荐答案

yc 是单个浮点数。

编译器将 symbol（）视为一个函数呼叫。这就是错误的含义。

The compiler treats symbol( ) as a function call. That is what the error means.

也许创建一个yc数组

float yc[gp];

并使用

yc[i] = ....

如突出显示- yc [gp] 可能不起作用，所以

As highlighted - yc[gp] may not work, so

float * yc = new float[gp];

在 main（）的末尾

delete []yc;

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