基本: . 
x
x-- 
typeof checked unchecked -> ::
元: + - ! ~ x --x (T)x True False & 
乘除: * / %
加减: + -
移位: << >>
关系: < > <= >= is as
相等: 
!=
逻辑: & ^ |
条件: && ||
赋值: = 
-= *= /= %= &= |= ^= <<= >>=
选择: ?: ??
其他: =>
整数 / 整数 = 整数
using 
;
MyClass
{
void Main
{
double d;
d = 14 / 4;
Console.WriteLine(d); //3
d = 14 / 4.0;
Console.WriteLine(d); //3.5
d = 14.0 / 4.0;
Console.WriteLine(d); //3.5
d = 14.0 / 4;
Console.WriteLine(d); //3.5
Console.WriteLine;
float f;
f = 14 / 4;
Console.WriteLine(f); //3
f = (float)(14.0 / 4.0); /* 默认返回 double, 因而需要转换 */
Console.WriteLine(f); //3.5
Console.WriteLine;
i;
i = 14 / 4;
Console.WriteLine(i); //3
i = ()(14.0 / 4.0);
Console.WriteLine(i); //3
i = 14 % 4;
Console.WriteLine(i); //2
Console.ReadKey;
}
} -- 可以对 double 类型using ;
MyClass
{
void Main
{
double f = 1.5;
f; Console.WriteLine(f); //2.5
f--; Console.WriteLine(f); //1.5
Console.WriteLine(f); //2.5
Console.WriteLine(--f); //1.5
Console.ReadKey;
}
}?:
using ;
MyClass
{
void Main
{
n, a=11, b=22;
n = a > b ? a : b;
Console.WriteLine(n); //22
n = a < b ? a : b;
Console.WriteLine(n); //11
Console.ReadKey;
}
}??
using ;
MyClass
{
void Main
{
? x = null; /* 给变量赋 null 
写法, 般用于数值和布尔类型 */
y;
y = x ?? -1; /* 如果 x 为 null 将返回后者, 反的返回 x */
Console.WriteLine(y); // -1
x = 9;
y = x ?? -1;
Console.WriteLine(y); // 9
Console.ReadKey;
}
}=>
using ;
using .Linq;
MyClass
{
void Main
{
n1, n2;
ns = {22, 333, 4444, 9};
n1 = ns.Max(num => num);
n2 = ns.Min(num => num);
Console.WriteLine("{0}, {1}", n1, n2); //4444, 9
ss = {"aaa", "bbbb", "ccccc", "dd"};
n1 = ss.Max(str => str.Length);
n2 = ss.Min(str => str.Length);
Console.WriteLine("{0}, {1}", n1, n2); //5, 2
Console.ReadKey;
}
}& | ^ !
using ;
MyClass
{
void Main
{
bool b;
b = true & true; Console.WriteLine(b); // True
b = true & false; Console.WriteLine(b); // False
b = false & false; Console.WriteLine(b); // False
b = true | true; Console.WriteLine(b); // True
b = true | false; Console.WriteLine(b); // True
b = false | false; Console.WriteLine(b); // False
b = true ^ true; Console.WriteLine(b); // False
b = true ^ false; Console.WriteLine(b); // True
b = false ^ false; Console.WriteLine(b); // False
b = !true; Console.WriteLine(b); // False
b = !false; Console.WriteLine(b); // True
Console.ReadKey;
}
}&& ||; 在条件判断时, 应尽量使用 &&、|| 而不是 &、|;
后者总是要计算出结果, 因而会慢.using ;
MyClass
{
void Main
{
bool b;
/* 在前两种情形下, && 不再判断其后值 */
b = false && true; Console.WriteLine(b); // False
b = false && false; Console.WriteLine(b); // False
b = true && true; Console.WriteLine(b); // True
b = true && false; Console.WriteLine(b); // False
/* 在前两种情形下, || 不再判断其后值 */
b = true || true; Console.WriteLine(b); // True
b = true || false; Console.WriteLine(b); // True
b = false || true; Console.WriteLine(b); // True
b = false || false; Console.WriteLine(b); // False
Console.ReadKey;
}
}
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