Linux 下监控程序升级版

#include<stdio.h>
#include<unistd.h>

class VMSTAT{
public:
        double stat[20];
        /*
        *       Proc
        *
        * 0:r: The number of processes waiting for run time.
        * 1:b: The number of processes in uninterruptible sleep.
        *
        *       Memory
        *
        * 2:swpd: the amount of virtual memory used.
        * 3:free: the amount of idle memory.
        * 4:buff: the amount of memory used as buffers.
        * 5:cache: the amount of memory used as cache.
        *
        *       Swap
        *
        * 6:si: Amount of memory swapped in from disk (/s).
        * 7:Amount of memory swapped to disk (/s).
        *
        *       IO
        *
        * 8:bi: Blocks received from a block device (blocks/s).
        * 9:bo: Blocks sent to a block device (blocks/s).
        *
        *       System
        *
        * 10:in: The number of interrupts per second, including the clock.
        * 11:cs: The number of context switches per second.
        *
        *       CPU
        *
        * 12:us: Time spent running non-kernel code. (user time, including nice time)
        * 13:sy: Time spent running kernel code. (system time)
        * 14:id: Time spent idle. Prior to Linux 2.5.41, this includes IO-wait time.
        * 15:wa: Time spent waiting for IO. Prior to Linux 2.5.41, included in idle.
        * 16:st: Time stolen from a virtual machine. Prior to Linux 2.6.11, unknown.
        *
        *       Add
        *
        * 17:Total Memory
        * 18:Used Memory
        * 19:CPU Usage
        */

        void update()
        {
                
                //init array
                FILE* file = popen("vmstat","r");
                char buf[300];
                fgets (buf , 300 , file);
                fgets (buf , 300 , file);
                fgets (buf , 300 , file);

                int index=0;
                for(int i = 0;i<300;i++)
                {
                        while(buf[i]<'0'||buf[i]>'9') i++;
                        int tmp = 0;
                        while(buf[i]>='0'&&buf[i]<='9')
                        {
                                tmp = tmp*10 + (buf[i]-'0');
                                i++;
                        }
                        stat[index++] = tmp*1.0;
                        if(index == 17) break;
                }
                pclose(file);
                
                
                //total memory
                file = popen("cat /proc/meminfo","r");  
                double total=0;  
                fgets (buf , 300 , file);  
                char str[7];  
                for(int i=17;i<24;i++)  
                        str[i-17]=buf[i];

                for(int i=0;i<7;i++)
                {
                        total =total*10+(str[i]==' '?0:(str[i]-'0'));
                }


                //calculate all
                stat[17]=total;
                stat[18]=total-stat[3];
                stat[19]=100-stat[14];
                pclose(file);


        }
        
};





int main()
{

        VMSTAT s;
        while(1){
                s.update();
                printf("Total: %d MB  Aviliable: %d MB  Used: %d MB  CPU: %d %\n",int(s.stat[17]/1000),int(s.stat[3]/1000),int(s.stat[18]/1000),int(s.stat[19]));
                sleep(1);
        }

        return 0;
}