C#学习之路，学习笔记 2.1 整形、浮点型和decimal型变量

<span style="font-size:14px;">using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace _1HellowTomorrow
{
class Program
{
static void Main(string[] args)
{
//变量定义
int a = 7;
int b = 2;
int sum, dif, pro, quo;

sum = a + b;
dif = a - b;
pro = a * b;
quo = a / b;

//输出到屏幕
Console.WriteLine("{0} + {1} = {2}", a, b, sum); //占位符的使用
Console.WriteLine("{0} - {1} = {2}", a, b, dif);
Console.WriteLine("{0} * {1} = {2}", a, b, pro);
Console.WriteLine("{0} / {1} = {2}", a, b, quo);

Console.WriteLine("Hellow Tomorrow");
//转换成2、8、16进制显示
Console.WriteLine(Convert.ToString(89, 2));
Console.WriteLine(Convert.ToString(89, 8));
Console.WriteLine(Convert.ToString(89, 16));

Console.WriteLine(Convert.ToString(25, 2));

//实数常量默认情况下是双精度的，为了把实数常量赋给单精度变量，需要
//添加后缀f或F，将其标志为单精度实数，比如：12.34567f   3.1415926F
float x = 3.14159265358979f;
double x1 = 3.14159265358979f;
//float x2 = 3.14159265358979;    此写法报错

double y = 3.14159265358979;
Console.WriteLine("x = {0}", x);
Console.WriteLine("x1 = {0}", x1);
//Console.WriteLine("x2 = {0}", x2);

Console.WriteLine("y = {0}", y);

//小明有44444.14元钱，小娟有66666.51元钱，编写一个程序，计算他们两个共有多少钱
float balanceOfMing = 44444.14f;
float balanceOfJuan = 66666.51f;

float total = balanceOfMing + balanceOfJuan;
Console.WriteLine("小明：￥{0}", balanceOfMing);
Console.WriteLine("小娟：￥{0}", balanceOfJuan);
Console.WriteLine("合计：￥{0}", total);  //结果应为111110.65，实则为111110.6
/* 出现精度不足的现象，
*
* 由此引入decimal型（128位）
* 注意！由于实数常量默认情况下为double型数据，要将其值赋给decimal型变量
* 需要添加后缀m或M，将其标记为decimal型数字
*/

//引入decimal后程序如下
decimal meonyOfMing = 44444.14m;
decimal meonyOfJuan = 66666.51m;
decimal sumOfThem = meonyOfJuan + meonyOfMing;
Console.WriteLine("小明：￥{0}", meonyOfMing);
Console.WriteLine("小娟：￥{0}", meonyOfJuan);
Console.WriteLine("合计：￥{0}", sumOfThem);  //正确

}
}
}
</span>

运行结果如下：

<img src="http://img.blog.csdn.net/20151001141603607?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" alt="" />