如何将 #include 添加到<iostream>项目中？

How to add #include <iostream> to project?

本文关键字：gt iostream 项目 lt #include 添加      更新时间：2023-10-16

我刚开始学习C++，我试图用Visual Studio 2017创建一个简单的代码。

#include "stdafx.h"
#include <iostream>
using namespace std;
int main()
{
int x;
std::cout >> "Enter Age";
std::cin >> x;
if (x >= 18) {
std::cout << "You are an adult." << endl;
}
else {
std::cout << "You are a child." << endl;
}
return 0;
}

但我想我收到了很多错误，例如iostream 不存在，因为我在头文件或 iostream.h 中没有看到它 我尝试创建一个新的头文件并简单地键入#include <iostream>但这似乎不起作用。这是我的错误。

1>c:usersmuntaonedrivedocumentsvisual studio 
2017projectsconsoleapplication3consoleapplication3source.cpp(8): error 
C2784: 'std::basic_istream<char,_Traits> &std::operator >>
(std::basic_istream<char,_Traits> &,signed char &)': could not deduce 
template argument for 'std::basic_istream<char,_Traits> &' from 
'std::ostream'
1>c:program files (x86)microsoft visual 
studio2017communityvctoolsmsvc14.10.25017includeistream(1068): 
note: see declaration of 'std::operator >>'
1>c:usersmuntaonedrivedocumentsvisual studio 
2017projectsconsoleapplication3consoleapplication3source.cpp(8): error 
C2784: 'std::basic_istream<char,_Traits> &std::operator >>
(std::basic_istream<char,_Traits> &,signed char *)': could not deduce 
template argument for 'std::basic_istream<char,_Traits> &' from 
'std::ostream'
1>c:program files (x86)microsoft visual 
studio2017communityvctoolsmsvc14.10.25017includeistream(1061): 
note: see declaration of 'std::operator >>'
1>c:usersmuntaonedrivedocumentsvisual studio 
2017projectsconsoleapplication3consoleapplication3source.cpp(8): error 
C2784: 'std::basic_istream<_Elem,_Traits> &std::operator >>
(std::basic_istream<_Elem,_Traits> &,_Elem &)': could not deduce template 
argument for 'std::basic_istream<_Elem,_Traits> &' from 'std::ostream'
1>c:program files (x86)microsoft visual 
studio2017communityvctoolsmsvc14.10.25017includeistream(1036): 
note: see declaration of 'std::operator >>'
1>c:usersmuntaonedrivedocumentsvisual studio 
2017projectsconsoleapplication3consoleapplication3source.cpp(8): error 
C2784: 'std::basic_istream<_Elem,_Traits> &std::operator >>
(std::basic_istream<_Elem,_Traits> &,_Elem *)': could not deduce template 
argument for 'std::basic_istream<_Elem,_Traits> &' from 'std::ostream'
1>c:program files (x86)microsoft visual 
studio2017communityvctoolsmsvc14.10.25017includeistream(995): note: 
see declaration of 'std::operator >>'
1>c:usersmuntaonedrivedocumentsvisual studio 
2017projectsconsoleapplication3consoleapplication3source.cpp(8): error 
C2676: binary '>>': 'std::ostream' does not define this operator or a 
conversion to a type acceptable to the predefined operator
1>Done building project "ConsoleApplication3.vcxproj" -- FAILED.

感谢您的任何帮助。

检查这个：std::cout >> "Enter Age";.我想它应该是std::cout << "Enter Age";。

顺便说一句，与问题无关，既然您正在编写std::cout和std::cin，那么最好与std::endl保持一致而不是endl.

问题出在第 8 行。它应该是：

std::cout << "Enter Age";
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