#include"iostream"
using namespace std;
class Class
{
private:
 int val;
public:
 void func(int a )
 {
  val=a;
  cout<<val<<endl;
 }
};
void main()
{
 Class *cls;
 cls->func(10);
}
谁来教我一下啊？

#include<iostream>
using namespace std;
class Class
{
private:
    int val;
public:
    void func(int a )
    {
        val=a;
        cout<<val<<endl;
    }
};
void main()
{
    Class *cls;
    cls=new Class;
    cls->func(10);
    delete cls;
}

为什么要用为指针cls开辟动态内存呀？

cls 未被初始化，指针变量申明时并未分配空间，除非被初始化。未分空间自然无法运行
#include"iostream"
using namespace std;
class Class
{
private:
int val;
public:
void func(int a )
{
  val=a;
  cout<<val<<endl;
}
};
void main()
{
Class *cls=new Class;   //new 一块内存以供开销
cls->func(10);
delete cls;
}

我明白了，谢谢你