C 传递指针给函数

#include <stdio.h>
#include <time.h>

void getSeconds(unsigned long *par);

int main ()
{
unsigned long sec;


getSeconds( &sec );

/* 输出实际值 */
printf("Number of seconds: %ldn", sec );

return 0;
}

void getSeconds(unsigned long *par)
{
/* 获取当前的秒数 */
*par = time( NULL );
return;
}

#include <stdio.h>

/* 函数声明 */
double getAverage(int *arr, int size);

int main ()
{
/* 带有 5 个元素的整型数组 */
int balance[5] = {1000, 2, 3, 17, 50};
double avg;

/* 传递一个指向数组的指针作为参数 */
avg = getAverage( balance, 5 ) ;

/* 输出返回值 */
printf("Average value is: %fn", avg );

return 0;
}

double getAverage(int *arr, int size)
{
int i, sum = 0;
double avg;

for (i = 0; i < size; ++i)
{
sum += arr[i];
}

avg = (double)sum / size;

return avg;
}