不能调用没有对象的成员函数 [英] cannot call member function without object
问题描述
此程序具有用户输入 name
/ age
对,然后使用类输出。
这是代码。
This program has the user input name
/age
pairs and then outputs them, using a class.
Here is the code.
#include "std_lib_facilities.h"
class Name_pairs
{
public:
bool test();
void read_names();
void read_ages();
void print();
private:
vector<string>names;
vector<double>ages;
string name;
double age;
};
void Name_pairs::read_names()
{
cout << "Enter name: ";
cin >> name;
names.push_back(name);
cout << endl;
}
void Name_pairs::read_ages()
{
cout << "Enter corresponding age: ";
cin >> age;
ages.push_back(age);
cout << endl;
}
void Name_pairs::print()
{
for(int i = 0; i < names.size() && i < ages.size(); ++i)
cout << names[i] << " , " << ages[i] << endl;
}
bool Name_pairs::test()
{
int i = 0;
if(ages[i] == 0 || names[i] == "0") return false;
else{
++i;
return true;}
}
int main()
{
cout << "Enter names and ages. Use 0 to cancel.\n";
while(Name_pairs::test())
{
Name_pairs::read_names();
Name_pairs::read_ages();
}
Name_pairs::print();
keep_window_open();
}
但是,在 int main()
当我试图调用函数时,我得到不能调用任何名称的函数没有对象。
我猜这是因为它的对于 variable.test
或 variable.read_names
。我应该如何解决这个问题?
However, in int main()
when I'm trying to call the functions I get "cannot call 'whatever name is' function without object."
I'm guessing this is because it's looking for something like variable.test
or variable.read_names
. How should I go about fixing this?
推荐答案
您需要实例化一个对象才能调用其成员函数。成员函数需要一个对象进行操作;他们不能只是自己使用。 main()
函数可以,例如,如下所示:
You need to instantiate an object in order to call its member functions. The member functions need an object to operate on; they can't just be used on their own. The main()
function could, for example, look like this:
int main()
{
Name_pairs np;
cout << "Enter names and ages. Use 0 to cancel.\n";
while(np.test())
{
np.read_names();
np.read_ages();
}
np.print();
keep_window_open();
}
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