void interchange(int * u,int * v)
{
    int temp = *u;  //带*号指向该地址上的值
    *u = *v;
    *v = temp;
}



int main1(void)
{
    int x = 10;
    int y = 5;
    printf("before: x = %d y = %d\n",x,y);
    interchange(&x,&y);
    printf("after: x = %d y = %d\n",x,y);
}

结果：

int sump(int *start, int *end)
{
    int total = 0;
    while(start < end)
    {
        total += *start;
        printf("%3d",*start);
        start++;  //每次移动int类型大小的位置
    }
    printf("\n");
    return total;
}

int main(void)
{
    int x[6] = {10,4,2,6,8,12};
    int sum;
    sum=sump(x,x+6);
    printf("%3d\n",sum);

}

结果：