顺序结构
if
Console.writeline("请输入跪键盘时间");
String strMin=console.readline();
Int min =console.ToInt32(strMin);
Bool result=min>60;
If(result)//条件或者是bool值
{
Console.writeline("不用给键盘了");
}
Console.readkey();
if...else
Console.WriteLine("请输入年份");
String year=Convert.ToInt32(Console.ReadLine());
bool result=(year%400==0)||(year%4==0&&year%100!=0);
if (result)
{
Console.WriteLine("闰年");
}
else
{
Console.WriteLine("不是闰年");
}
Console.ReadKey();
if...else if...
string str = "";
Console.WriteLine("输入成绩");
int score = Convert.ToInt32(Console.ReadLine());
if (score>=90)
{
str="A";
}
else if(score>=80)
{
str="B";
}
else if(score>=70)
{
str="C";
}
else if(score>=60)
{
str="D";
}
else
{
str="E";
}
Console.WriteLine(str);
Console.ReadKey();
switch-case
是多分支结构
switch (num)
{
case 1: per[i] = new Person(); break;
case 2: per[i] = new Teacher(); break;
case 3: per[i] = new Student(); break;
case 4: per[i] = new ShuaiGuo(); break;
case 5: per[i] = new MeiLv(); break;
case 6: per[i] = new YeShou(); break;
}
try-carch
异常处理
try
{
int num = Convert.ToInt32(Console.ReadLine());
}
catch (Exception ex)
{
throw;//专门扔出来异常
Console.WriteLine(ex.Message);
}
//无论是否出异常都走这里
finally
{
Console.WriteLine("杨洋好帅");
}
Console.ReadKey();
循环结构
while循环
先判断,然后再执行循环体
循环可以一次都不执行
//2006年培养学员80000人,每年增长25%,请问按此增长速度,
//到哪一年培训学员人数将达到20万人?
double student = 80000;
int year = 2006;
while (student<=200000)
{
student *= 1.25;
year++;
}
Console.WriteLine("{0}年是{1}人",year,student);
Console.ReadKey();
do-while循环
先执行一次循环,然后再判断条件是否成立
循环至少会执行一次
String name ="";
String pwd="";
do
{
Console.WriteLine("请输入账号");
name=Console.ReadLine();
Console.WriteLine("请输入密码");
pwd=Console.ReadLine();
}while (name!="admin"||pwd!="8888");
Console.WriteLine("程序结束");
Console.ReadKey();
for循环
//求1-100间的所以偶数和
int sum=0;
for(int i=0; I <= 100; i++)
{
if (i%2==0)
{
sum += I;
}
}
Console.WrteLine("总和为{0}",sum);
Console.ReadKey();
foreach
提供了遍历数组的简单方式
foreach (array_expression as value)
statement
跳转语句
break
用于循环中,退出当前循环
int i=0;
while(true)
{
if(i==5)
{
Console.WriteLine("小羊很帅");
break;
}
i++;
}
Console.WriteLine("系统识别此话是真的");
Console.ReadKey();
continue
int i=1;
int sum=0;
while (i <= 100)
{
if (i % 7 == 0)
{
i++;
continue;
}
sum += i;
i++;
}
Console.WriteLine("总和为{0}",sum);
Console.ReadKey();