C++实现页面置换算法（操作系统实验课）--【FIFO与LRU】

#include <iostream>
#include <stdio.h>
#include <fstream>
#include <vector>
#include <string>
using namespace std;
int page = 3;
int Check(vector<int> b, int a) {//检查内存中是否存在该页
    for (int i = 0; i < b.size(); i++) {
        if (b[i] == a) return i;//存在返回下标
    }
    return -1;//不存在，返回-1
}
void FIFO(vector<int> a) //先进先出算法
{
    cout << "FIFO算法\n";
    vector<int> b;
    int num = 0;
    //cout << "访问页面    内存块中存在  \t   是否缺页" << endl;
    for (int i = 0; i < a.size(); i++) {
        cout << "访问页面:" << a[i] << "\t"<<"内存块中存在:";
        for (int j = 0; j < b.size(); j++)
            cout << b[j] << " ";//输出内存块中的页
        cout << "\t";
        if (Check(b, a[i])!=-1)//不缺页
            cout << "是否缺页:否\n";
        else {//缺页
            cout << "是否缺页:是     ";
            if (b.size() == page) {//内存满
                cout << "淘汰页:" << b[0] << endl;
                b.erase(b.begin());
            }
            else cout << endl;
            b.push_back(a[i]);
            num++;
        }
    }
    cout << "最终内存中有：";
    for (int j = 0; j < b.size(); j++)
        cout << b[j] << " ";
    cout << endl<<"缺页次数为：" << num << " 缺页率为:";
    double l = num * 100.0 / a.size();
    printf("%.2f%%\n", l);
}
struct lru
{
    vector<int> name;
    vector<int> time;
};
void LRU(vector<int> a) //最近最久未使用算法
{
    cout << "LRU算法\n";
    lru b;
    int num = 0;
    //cout << "访问页面    内存块中存在\t   是否缺页" << endl;
    for (int i = 0; i < a.size(); i++) {
        cout << "访问页面:" << a[i] << "\t"<<"内存块中存在:";
        for (int k = 0; k < b.time.size(); k++)
            b.time[k]++;//所有页未使用时间加1
        for (int j = 0; j < b.name.size(); j++)
            cout << b.name[j] << " ";
        cout << "\t";
        int check = Check(b.name, a[i]);
        if (check != -1) {//不缺页
            cout << "是否缺页:否\n";
            b.time[check] = 0;//刚使用过的页,time置0
        }
        else {//缺页
            cout << "是否缺页:是     ";
            if (b.name.size() == page)//内存满
            {
                int it, maxit = 0;
                for (int j = 0; j < b.time.size(); j++) {//找time最大(最久未使用)的下标
                    if (maxit < b.time[j]) {
                        maxit = b.time[j];
                        it = j;
                    }
                }
                cout << "淘汰页:" << b.name[it] << endl;
                b.name.erase(b.name.begin() + it);
                b.time.erase(b.time.begin() + it);
            }
            else cout << endl;
            b.name.push_back(a[i]);
            b.time.push_back(0);
            num++;
        }
    }
    cout << "最终内存中有：";
    for (int j = 0; j < b.name.size(); j++)
    {
        cout << b.name[j] << " ";
    }
    cout << endl;
    cout << "缺页次数为："<<num<<" 缺页率为:";
    double l = num * 100.0 / a.size();
    printf("%.2f%%", l);
}
void OPT(vector<int> a) {

}
int main() {
    vector<int> a;
    ifstream ifs("1.txt", ios::in);
    string s;
    if (!ifs) {
        cout << "打开失败";
        return 0;
    }
    getline(ifs, s);
    cout << s << endl;
    ifs.close();
    for (int i = 0; i < s.length(); i = i + 2) {
        a.push_back(s[i] - '0');
    }
    FIFO(a);
    LRU(a);
    return 0;
}