数组下标的类型无效

Question

我遇到了一个非常奇怪的C++错误，我无法完成。我以前初始化数百个阵列，但由于某些原因，当我让双打的数组：

double trap[]={0.0,0.0,0.0,0.0,0.0,0.0}; 

然后尝试做任何事情与此阵的具体内容，即：

cout << trap[3] << endl; 

我得到了奇怪的错误：

compare.cpp:43:20: error: invalid types ‘double[int]’ for array subscript 
cout << trap[3] << endl; 

我根本不理解。为什么下标（整数）与该元素中包含的值的类型（双精度）有什么关系？

编辑：这是我认为是给错误全码：

#include <stdio.h> 
#include <math.h> 
#include <cmath> 
#include <iostream> 
#include <iomanip> 

using namespace std; 

const double Xmax[]={2.0,10.0,20.0,40.0, 80.0, 160.0}; 

double f (double x) { 
    return (exp(-x));    
} 

int main() { 
    FILE *Trap = fopen("trap.dat","w"); 

    double trap[]={0.0,0.0,0.0,0.0,0.0,0.0}, 

cout << gaus2_old[3] << endl; 
//...do other stuff with trap[] and Xmax[]... 
} 

这里的一切在该行“做其他的东西与陷阱[]和的Xmax []”是我的代码只是休息，其中阱的每个实例[]和的Xmax []给出相同的错误：

compare.cpp:43:20: error: invalid types ‘double[int]’ for array 

Answer 1

我运行在VS此代码和它打印0到控制台。

// testcpp.cpp : Defines the entry point for the console application. 
// 

#include "stdafx.h" 
#include <iostream> 

using namespace std; 
int _tmain(int argc, _TCHAR* argv[]) 
{ 
    double trap[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 }; 
    cout << trap[3] << endl; 

    return 0; 
} 

上更新：我同意https://stackoverflow.com/users/5289220/sukces-elektroniki，更改

double trap[]={0.0,0.0,0.0,0.0,0.0,0.0}, 

到

double trap[]={0.0,0.0,0.0,0.0,0.0,0.0}; 

和

变化

cout << gaus2_old[3] << endl; 

到

cout << trap[3] << endl;