linux c读取CPU和内存的使用情况

/**
* get cpu and memory info
* wangzeng 2009.05.04
*/
#include<stdio.h>
#include<unistd.h>
#include<time.h>
#include<sys/types.h>

//cpu
struct cpustatus
{
        long  total;
        float user;
        float nice;
        float system;
        float idle;
};

//memory
struct meminfo
{
        char total[20];
        char free[20];
};

void errmsg(char *msg);
void get_cpu_status(struct cpustatus *);
void get_mem_info(struct meminfo *);
void write_log(struct cpustatus *,struct meminfo *);

int main(int ac,char *av[])
{
struct cpustatus cpu_stat;
struct meminfo mem_info;
get_cpu_status(&cpu_stat);
printf("user\t nice\t system\t idle\n");
printf("%4.2f\t %4.2f\t %4.2f\t %4.2f\n",cpu_stat.user,cpu_stat.nice,cpu_stat.system,cpu_stat.idle);
get_mem_info(&mem_info);
printf("total:\t%s\n",mem_info.total);
printf("free:\t%s\n",mem_info.free);
write_log(&cpu_stat,&mem_info);
return 0;
}

//deal error
void errmsg(char *msg)
{
        perror(msg);
        exit(1);
}

// start write cpu and memory info by applend mode
void write_log(struct cpustatus *cpu_stat,struct meminfo *mem_info)
{
FILE *fp;
long seconds;
if((fp=fopen("cpustatuslog.txt","a+"))==NULL)
        errmsg("open cpustatuslog.txt error\n");
else
        {
        seconds=time((time_t*)NULL);
        fprintf(fp,"%s",ctime(&seconds));
        fprintf(fp,"user\t nice\t system\t idle\n");
        fprintf(fp,"%4.2f\t %4.2f\t %4.2f\t %4.2f\n",cpu_stat->user,cpu_stat->nice,cpu_stat->system,cpu_stat->idle);
        fprintf(fp,"total:\t%s\n",mem_info->total);
        fprintf(fp,"free:\t%s\n",mem_info->free);
        fprintf(fp,"-------------------------------\n\n");
        fclose(fp);
        }
}

// get cpu status
void get_cpu_status(struct cpustatus *cpu_stat)
{
        unsigned int total;
        float   user;
        float   nice;
        float   system;
        float   idle;
        char   cpu[21];
        char   text[201];
        FILE   *fp;
        fp=fopen("/proc/stat","r");
        while(fgets(text,200,fp))
        {
             if(strstr(text,"cpu"))
              {
               sscanf(text,"%s %f %f %f %f",cpu,&user,&nice,&system,&idle);          }
        }
        fclose(fp);
        total=(user+nice+system+idle);
        user=(user/total)*100;
        nice=(nice/total)*100;
        system=(system/total)*100;
        idle=(idle/total)*100;
        cpu_stat->total=total;
        cpu_stat->user=user;
        cpu_stat->nice=nice;
        cpu_stat->system=system;
        cpu_stat->idle=idle;
        return;
}

//get memory info
void get_mem_info(struct meminfo *minfo)
{
        FILE *fp;
        int i,j;
        char total[20];
        char free[20];
        char temp[80];
        if((fp=fopen("/proc/meminfo","r"))==NULL)
                errmsg("open meminfo error.\n");
        else
        {
                for(i=0;i<5;i++)
                {
                        fgets(temp,80,fp);
                        if(i==3) //total info at 3 row
                                strcpy(total,temp);
                        if(i==4) //free info at 4 row
                                strcpy(free,temp);
                }
        }
        if(strlen(total)>0)
        {
                for(i=0,j=0;i<strlen(total);i++)
                {
                        if(isdigit(total[i]))
                                minfo->total[j++]=total[i];
                }
                minfo->total[j]='\0';
        }
        if(strlen(free)>0)
        {
                for(i=0,j=0;i<strlen(free);i++)
                {
                        if(isdigit(free[i]))
                                minfo->free[j++]=free[i];
                }
                minfo->free[j]='\0';
        }
        return;
}