编译器错误 C2679：没有找到接受“MyInteger”类型的右操作数的运算符(或没有可接受的转换)

#include <iostream>
#include <string>
#include <vector>
using namespace std;

class MyInteger {
   
	friend ostream& operator<<(ostream& cout, MyInteger& myint);
private:
	int m_A;
public:
	MyInteger() {
   
		m_A = 0