Student.h头文件内容：

#pragma once
#include <string>
using namespace std;

class Student
{
public:
	string name;
	int score;
	static int totalScore; // 静态局部变量声明

	Student(string name, int score);

	~Student();

	void print() const;
};

Student.cpp源文件内容：

#include "Student.h"
#include <iostream>

Student::Student(string name, int score) : name(name), score(score) {
	Student::totalScore += score;
}

int Student::totalScore = 0; // 静态成员变量定义和初始化, 必须

Student::~Student() {
	cout << "student: " << name << " 析构" << endl;
}

void Student::print() const {
	cout << "student: " << name << ", my score:" << score << " , all students' total score: " << Student::totalScore << endl;
}

测试代码：

#include "Student.h"

void testStaticVal() {
	Student* stu1 = new Student("隔壁老王", 60);
	stu1->print();
	Student* stu2 = new Student("隔壁老宋", 80);
	stu2->print();

	delete stu1;
	delete stu2;
	std::cout << "totalScore: " << Student::totalScore << std::endl;
}

打印：

ok. 静态成员变量属于类，在全局数据区分配内存。