Linux C语言，实例程序

判断输入是否合理
#include <iostream.h>
void main()
{ 
         unsigned int age;
         cout <<"what is the student's age...";
         cin >> age;
         if  (age<10)
             cout << "the age may be wrong";
} 

判断是否为闰年

#include <iostream.h>
void main()
{
      int year;
      cout << "please input a year...";
       cin >> year;
      if  (year %4==0 && year % 100 !=0 || year % 400 == 0)
       cout << "The year is leap year ";
      else
       cout << "The year isn't leap year ";
}


输入两个整数，判断大小：

#include <iostream.h>
void main()

{
     int x,y;
     cout << "Enter x and y:";
     cin>>x>>y;
     if (x!=y)
        if (x>y)
           cout << "x>y"<<endl;
        else
           cout << "x<y" <<endl;
     else 
        cout << "x=y" << endl;
}

求三个数中的最大数：
方法一：
#include <iostream.h>
void main()
{
   int x,y,z;
   cin >>x>>y>>z;
   int max=x;
   if (z>y)
     {
       if (z>x)
         max=z;
      }
   else
     {
       if (y>x)
         max=y;