初学C++，自己写的几个小程序。

#include <iostream>
#include <string>
using namespace std;
int main()
{
    for (int i = 1; i <= 5; i++)
    {
        for (int j = 1; j<=5-i; j++)
        {
            cout << " ";
        }   
        for (int k = 1; k<=i*2-1; k++)
        {
            cout << "*";
        }
        cout << endl;
    }
    return 0;
}

#include <iostream>
int main()
{
    int iSecond = 32432 , iTest = 0 , iMark = 0 , iHour = 0;
    iHour = iSecond / 3600;  //求小时
    iTest = iSecond % 3600;  //小时余下来的秒
    if (iTest >= 60) //如果大等于60秒就计算分
    {
        iMark = iTest / 60;
        iSecond = iTest % 60;
    }
    else
    {
        iSecond = iTest;
    }
    printf("%d小时" , iHour);
    printf("%d分钟" , iMark);
    printf("%d秒" , iSecond);
    return 0;
}

#include <iostream>

int main()
{
    for (int i = 1; i <= 9; i++)
    {
        for (int k = 1; k<=i; k++)
        {
            printf("%2d" , k);
            printf("*");
            printf("%2d" , i);
            printf("=");
            printf("%2d" , k * i);            
        }
        printf("\n");
    }
    return 0;
}

#include <iostream>
void WeenDay(int Wday);        //求星期函数
bool Runyear(int iyear);       //判断闰年函数
int YearCount(int Syear , int Lyear , int Month , int Day);   //求天数函数
int iMonth[12] = {31 , 28 , 31 , 30 , 31 , 30 , 31 , 31 , 30 , 31 , 30 , 31};  //月数
int main()
{
    int iStarYear = 1900 , iStarMonth = 1 , iStarDay = 1 , iStarWeenday = 1;
    int iLastYear , iLastMonth , iLastday;
    printf("请输入年:");
    scanf("%d" , &iLastYear);
    printf("请输入月:");
    scanf("%d" , &iLastMonth);
    printf("请输入日:");
    scanf("%d" , &iLastday);
    int iDaynum = YearCount(iStarYear , iLastYear , iLastMonth , iLastday);  //调出天数
    WeenDay(iDaynum);   //调出星期数
    return 0;
}

bool Runyear(int iyear)
{
   
    if ((iyear % 4 == 0 && iyear % 100 != 0) || (iyear % 100 ==0 && iyear % 400 == 0))
    {
        return true;    //闰年   
    }
        return false;    //平年   
}

void WeenDay(int Wday)
{
    int iWday[7] = {1 , 2 , 3 , 4 , 5 , 6 , 7};   //用一个数组来显示星期数
    int iDay = iWday[Wday % 7];       //用总共的天数除7得余数赋给变量iday
    printf("星期%d\n",iDay);   
}

int YearCount(int Syear , int Lyear , int Month , int Day)
{
    int iYearnum = 0;
    int iDayCount;
   
    for (int i = Syear ; i < Lyear ; i++)  //用一个循环得出除了最后一年的所有的天数
    {
        
        if (Runyear(i))   //如果是闰年那么今年总共有366天
        {
            iDayCount = 366;
        }
        else
        {
            iDayCount = 365; //如果是平年那么今年总共有365天
        }
        iYearnum += iDayCount;
    }
   
    if (Runyear(Lyear))  //如果是闰年那么二月份总共有29天
    {        
        iMonth[1] = 29;
    }
    else   //如果是平年那么二月份总共有28天
    {            
        iMonth[1] = 28;
    }
   
    for ( i = 0 ; i < Month - 1 ; i++)  //用循环算出除了最后一个月的所有天数
    {
        iYearnum += iMonth[i];
    }
   
    iYearnum += Day;  //最后加上最后一个月的天数
   
    return iYearnum-1;   //注：这个地方减一是因为数组iWday[7]是从0开始的
}