[英]why cant my c++ code show cout string
this is my main.cpp 这是我的main.cpp
#include <iostream>
using namespace std;
#include "test.h"
void main()
{
Solution aa;
aa.aaa();
cin.get();
}
this is my test.h 这是我的测试。
#pragma once
class Solution {
public:
void aaa() {};
};
this is my test.cpp 这是我的test.cpp
#include <iostream>
using namespace std;
class Solution {
public:
void aaa() {
cout << "aaaaa" << endl;
};
};
and when I run the c++ code, it shows nothing. 当我运行c ++代码时,它什么也没显示。 Can anybody tell me why?
谁能告诉我为什么?
Your test.h
declared and defined a Solution
class, with an aaa()
class method that does absolutely nothing. 您的
test.h
使用绝对不做任何事情的aaa()
类方法声明并定义了Solution
类。
void aaa() {};
See, the aaa()
method does nothing. 看到,
aaa()
方法什么也不做。
Your main()
called this method, that does absolutely nothing. 您的
main()
称为此方法,它绝对不执行任何操作。
End result: nothing happened, as expected. 最终结果:未发生任何意外。
You also happened to have a test.cpp
that happened to declare and define its own class, of the same name. 您还碰巧有一个
test.cpp
,它恰好声明并定义了自己的同名类。 At the very least, this is undefined behavior, and I would point my finger and laugh at any C++ compiler+linker that decided that there was nothing wrong with linking together both main.cpp
and test.cpp
. 至少,这是未定义的行为,我会对所有决定将
main.cpp
和test.cpp
链接在一起都没有错的C ++编译器+链接器大加test.cpp
。
In test.h: 在test.h中:
void aaa() {};
Notice that you put empty brackets instead of just a semicolon after the (). 请注意,您在()后面放了空括号,而不仅仅是分号。 If you want to write a function declaration you just write the function name and parameters but not the brackets.
如果要编写函数声明,则只需编写函数名称和参数,而不要括号。 Now the compiler thinks that you want to write a function that does nothing.
现在,编译器认为您想编写一个不执行任何操作的函数。 (I'm surprised that this didn't cause a linking error)
(我很惊讶这没有引起链接错误)
Your test.h
and test.cpp
files are implemented incorrectly. 您的
test.h
和test.cpp
文件实施不正确。 They should look more like this instead: 他们应该看起来像这样:
test.h 测试
#pragma once
class Solution {
public:
void aaa();
};
test.cpp 测试文件
#include "test.h"
#include <iostream>
using namespace std;
void Solution::aaa() {
cout << "aaaaa" << endl;
}
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