[C++知识库]c++实现成绩管理系统

成绩管理系统

	1.增加学生信息
	2.删除学生
	3.修改学生
	4.列出
	5.查找
	0.退出  把学生信息保存到文件

#include <iostream>
#include <fstream>
#include <algorithm>
#include <cstring>
#include <vector>
using namespace std;


class Stu{
private:
	int no;
	string name;//name 对象  char name[20];   ifs.read  ofs.write
	int s[3];
public:
	Stu(){}
	Stu(int no):no(no){}
	Stu(int no,string name,int s[]){
		this->no = no;
		this->name = name;
		memcpy(this->s,s,sizeof(this->s));
	}
	
	bool operator==(const Stu& s)const{
		return no == s.no;	
	}
	
	friend ostream& operator<<(ostream& os,const Stu& s);
	friend istream& operator>>(istream& is,Stu &s);
};

ostream& operator<<(ostream& os,const Stu& s){
	os << s.no << " " << s.name;
	for(int i=0;i<3;i++)
		os << " " << s.s[i];
	return os<<endl;
}

istream& operator>>(istream& is,Stu &s){
	is >> s.no >> s.name;
	for(int i=0;i<3;i++)
		is >> s.s[i];
	return is;
}

void load(vector<Stu>& vs){
	ifstream ifs("stu.dat");
	while(!ifs.eof()){
		Stu s;
		ifs >> s;//ifs.read((char*)&s,sizeof(s));  不能有指针成员
		if(!ifs.eof()){
			vs.push_back(s);
			cout << s ;
		}
	}
	ifs.close();
}

void save(vector<Stu>& vs){
	ofstream ofs("stu.dat",ios::out|ios::trunc);
	vector<Stu>::iterator it;
	for(it=vs.begin();it!=vs.end();it++){
		ofs << *it;//ofs.write((char*)&*it,sizeof(*it));
	}
}
void add(vector<Stu>& vs){
	Stu s;
	cout << "no name s[3]:";
	cin >> s;
	vs.push_back(s);
}
/*
vector<Stu>::iterator find(vector<Stu>& vs,Stu& s){
	vector<Stu>::iterator it;
	for(it = vs.begin();it!=vs.end();it++){
		if(*it == s){
			return it;	
		}	
	}
	return vs.end();
}
*/
void list(vector<Stu>& vs){
	vector<Stu>::iterator it;
	cout << "no  name  s" << endl;
	for(it=vs.begin();it!=vs.end();++it){
		cout << *it;	
	}
}

void find(vector<Stu>& vs){
	int no;
	cout << "input stu's no:";
	cin >>  no;
	Stu s(no);
	//vector<Stu>::iterator it = find(vs,s);
	vector<Stu>::iterator it = find(vs.begin(),vs.end(),s);
	if(it != vs.end()){
		cout << *it;	
	}else{
		cout << "查无此人" << endl;	
	}
}

void del(vector<Stu>& vs){
	int no;
	cout << "input stu's no:";
	cin >> no;
	Stu s(no);
	//vector<Stu>::iterator it = find(vs,s);
	vector<Stu>::iterator it = find(vs.begin(),vs.end(),s);
	if(it != vs.end()){
		cout << *it;
		vs.erase(it);
	}else{
		cout << "查无此人" << endl;	
	}
}

void mod(vector<Stu>& vs){
	Stu s;
	cout << "input stu:";
	cin >> s;
	//vector<Stu>::iterator it = find(vs,s);
	vector<Stu>::iterator it = find(vs.begin(),vs.end(),s);
	if(it != vs.end()){
		cout << *it;
		*it = s;
		cout << *it;
	}else{
		cout << "查无此人" << endl;	
	}
}


void run(){
	vector<Stu> vs;
	load(vs);
	while(true){
		cout << "成绩管理系统" << endl;
		cout << "1.增加学生" << endl;
		cout << "2.列出" << endl;
		cout << "3.查找" << endl;
		cout << "4.删除" << endl;
		cout << "5.修改" << endl;
		cout << "0.退出" << endl;
		cout << "input:";
		int opt = 0;
		cin >> opt;
		switch(opt){
			case 1:
				add(vs);
				break;
			case 2:
				list(vs);
				break;
			case 3:
				find(vs);
				break;
			case 4:
				del(vs);
				break;
			case 5:
				mod(vs);
				break;
			case 0:
				save(vs);
				return;
		}
	}
	
}
int main(){
	run();
	return 0;
}