int GetIntegerInRange(int low, int high)
{
　 int res;
　 do {
　　 cout << "Enter an integer in the range " << low
　　 << " ... " << high << " :";
　　 cin >> res;
　　 } while (! ((res >= low) && (res <= high)));
return res;
}

以上是我从C++教程中的函数定义一章里找出来的。
其中 int low, int high 书上说是参数。
我不明白参数的意义，书上也说不清楚。因此我想向大家求教呀。
况且int low, int high有定义值吗，为什么RES作比较：res >= low) && (res <= high

晕。。。。。。。。。。。。求救呀！！！！！！！！！！！

那int GetIntegerInRange(3, 7)中3 ；7是你举的例子，还是怎样的。
还有这个参数是怎样运用的？

#include <iostream.h>
void Foo (int first, int second, int third)
{
　 cout << "Original function values "
　 << "first = " << first
　 << "second = " << second
　 << "third = " << third
　 <<endl;
　 first += 50;
　 second += 50;
　 third += 50;
　 cout << "Ending function values "
　 << "first = " << first
　 << "second = " << second
　 << "third = " << third
　 <<endl;
}
void main (void)
{
　 int x = 1, y = 2, z = 3;
　 Foo(x,y,z);
　 cout << "Ending values in main "
　 << "first = " << x
　 << "second = " << y
　 << "third = " << z
　 <<endl;
}


　　 编译并执行，屏幕将显示如下结果：
　　 Original function values first = 1 second = 2 third = 3
　　 Ending function values first = 51 second = 52 third = 53
　　 Ending values in main first = 1 second = 2 third = 3

像以上程序，fisrt second third 是在什么时候赋值的呢？
int x = 1, y = 2, z = 3
中吗？
可是是void Foo函数先运行的吧。
还不是很理解。