用C++提取Linux内存的使用率

//程序实现的功能是，通过把内存使用的情况读入文本文件再存入变量#include<stdio.h>#include<unistd.h>#include<stdlib.h>#include<iostream>#include<fstream>#include<string.h>using namespace std;class A{public:void display(){system("df -m |grep /dev/sda1 | cut -d ' ' -f 9 >>webnode_size.txt");//把读得的以M为单位的内存数据存入文本文件system("df -m |grep /dev/sda1 | cut -d ' ' -f 13 >>webnode_avail.txt");system("df -m |grep /dev/sda3 | cut -d ' ' -f 14 >>detectnode_size.txt");system("df  -m |grep /dev/sda3 | cut -d ' ' -f 19 >>detectnode_avail.txt");}};class B: public A{public:void b_size(){//string b_size;double b_size;ofstream outfile;outfile.open("webnode_size.txt",ios::out);//A a;A::display();ifstream infile;infile.open("webnode_size.txt",ios::in);infile>>b_size;cout<<b_size<<endl;infile.close();}void b_avail(){//string b_avail;double b_avail;ofstream outfile;outfile.open("webnode_avail.txt",ios::out);//A a;A::display();ifstream infile;infile.open("webnode_avail.txt",ios::in);infile>>b_avail;cout<<b_avail<<endl;infile.close();}void c_size(){//string c_size;double c_size;ofstream outfile;outfile.open("detectnode_size.txt",ios::out);//A a;A::display();ifstream infile;infile.open("detectnode_size.txt",ios::in);infile>>c_size;cout<<c_size<<endl;infile.close();}void c_avail(){//string c_avail;double c_avail;ofstream outfile;outfile.open("detectnode_avail.txt",ios::out);//A a;A::display();ifstream infile;infile.open("detectnode_avail.txt",ios::in);infile>>c_avail;cout<<c_avail<<endl;infile.close();}};int main(){//A a;//a.display();//A::display();B b,c,d,e;b.b_size();c.b_avail();d.c_size();e.c_avail();cout<<"the process is ok!"<<endl;return 0;}