linux c程序获取cpu使用率及内存使用情况

想获取一下目标机运行时linux系统的硬件占用情况，写了这几个小程序，以后直接用了。
方法就是读取proc下的文件来获取了。 cpu使用率： /proc/stat ，内存使用情况： /proc/meminfo
看程序 ：
/***************************************************************
* @file: statusinfo.c
*
* @brief: 从linux系统获取cpu及内存使用情况
*
* @version 1.0
*
* @author 抹黑
*
* @date 2009年3月17日
*
***************************************************************/
typedef struct PACKED //定义一个cpu occupy的结构体
{
char name[20]; //定义一个char类型的数组名name有20个元素
unsigned int user; //定义一个无符号的int类型的user
unsigned int nice; //定义一个无符号的int类型的nice
unsigned int system;//定义一个无符号的int类型的system
unsigned int idle; //定义一个无符号的int类型的idle
}CPU_OCCUPY;

typedef struct PACKED //定义一个mem occupy的结构体
{
char name[20]; //定义一个char类型的数组名name有20个元素
unsigned long total;
char name2[20];
unsigned long free;
}MEM_OCCUPY;

get_memoccupy (MEM_OCCUPY *mem) //对无类型get函数含有一个形参结构体类弄的指针O
{
FILE *fd;
int n;
char buff[256];
MEM_OCCUPY *m;
m=mem;

fd = fopen ("/proc/meminfo", "r");

fgets (buff, sizeof(buff), fd);
fgets (buff, sizeof(buff), fd);
fgets (buff, sizeof(buff), fd);
fgets (buff, sizeof(buff), fd);
sscanf (buff, "%s %u %s", m->name, &m->total, m->name2);

fgets (buff, sizeof(buff), fd); //从fd文件中读取长度为buff的字符串再存到起始地址为buff这个空间里
sscanf (buff, "%s %u", m->name2, &m->free, m->name2);

fclose(fd); //关闭文件fd
}

int cal_cpuoccupy (CPU_OCCUPY *o, CPU_OCCUPY *n)
{
unsigned long od, nd;
unsigned long id, sd;
int cpu_use = 0;

od = (unsigned long) (o->user + o->nice + o->system +o->idle);//第一次(用户+优先级+系统+空闲)的时间再赋给od
nd = (unsigned long) (n->user + n->nice + n->system +n->idle);//第二次(用户+优先级+系统+空闲)的时间再赋给od

id = (unsigned long) (n->user - o->user); //用户第一次和第二次的时间之差再赋给id
sd = (unsigned long) (n->system - o->system);//系统第一次和第二次的时间之差再赋给sd
if((nd-od) != 0)
cpu_use = (int)((sd+id)*10000)/(nd-od); //((用户+系统)乖100)除(第一次和第二次的时间差)再赋给g_cpu_used
else cpu_use = 0;
//printf("cpu: %u\n",cpu_use);
return cpu_use;
}

get_cpuoccupy (CPU_OCCUPY *cpust) //对无类型get函数含有一个形参结构体类弄的指针O
{
FILE *fd;
int n;
char buff[256];
CPU_OCCUPY *cpu_occupy;
cpu_occupy=cpust;

fd = fopen ("/proc/stat", "r");
fgets (buff, sizeof(buff), fd);

sscanf (buff, "%s %u %u %u %u", cpu_occupy->name, &cpu_occupy->user, &cpu_occupy->nice,&cpu_occupy->system, &cpu_occupy->idle);

fclose(fd);
}

int main()
{
CPU_OCCUPY cpu_stat1;
CPU_OCCUPY cpu_stat2;
MEM_OCCUPY mem_stat;
int cpu;

//获取内存
get_memoccupy ((MEM_OCCUPY *)&mem_stat);

//第一次获取cpu使用情况
get_cpuoccupy((CPU_OCCUPY *)&cpu_stat1);
sleep(10);

//第二次获取cpu使用情况
get_cpuoccupy((CPU_OCCUPY *)&cpu_stat2);

//计算cpu使用率
cpu = cal_cpuoccupy ((CPU_OCCUPY *)&cpu_stat1, (CPU_OCCUPY *)&cpu_stat2);

return 0;
}