我正在尝试编写一个简单的程序来使用欧拉方法计算数值近似值,而我使用的每个编译器都没有打印任何内容。Codeblocks 运行错误,但我认为这是因为编译器设置不正确。xCode 将构建它,但没有任何反应。当我运行 g++ Euler.cpp 时,我得到:
Euler.cpp:1: error: expected constructor, destructor, or type conversion before ‘<’ token
Euler.cpp: In function ‘int main()’:
Euler.cpp:13: error: ‘cin’ was not declared in this scope
Euler.cpp:19: error: ‘cout’ was not declared in this scope
Euler.cpp:19: error: ‘endl’ was not declared in this scope
我通常不会遇到简单的 C++ 程序的问题,并且担心这是非常明显的事情。
//
// Euler.cpp
// Numerical Approximations (Euler's Method)
//
// Created by XXXXXXXXXXXX on 6/18/12.
// Copyright (c) 2012 University of Kansas Department of Mathematics. All rights reserved.
//
#include <iostream>
using namespace std;
int main ()
{
int N=4;
//cout<<"Number of steps (N):";
//cin>>t;
float h=0.1;
//cout<<endl<<" Step size (h):";
cin>>h;
float y0=1;
//cout<<endl<<"y(0)=";
//cin>>y0;
cout<<"test!"<<endl;
float data[N][4];
int n=0;
data[0][2] = y0;
while (n<N){
data[n][0]=n;
if(n>0){
data[n][2]=data[n-1][3];
}
data[n][1]=h*n;
data[n][3] = data[n][2] + ((3 + data[n][1] - data[n][2])*h);
n++;
cout<<"n="<<n<<". tn="<<data[n][1]<<". y(n)="<<data[n][2]<<". y(n+1)="<<data[n][3] <<"."<<endl;
}
return 0;
}
这可能是显而易见的,但我没有看到。