class Program19
{
static void Main(string[] args)
{
// true，或false
Console.WriteLine("bool占用:" + sizeof(bool));
//0-255
Console.WriteLine("byte 占用:"+sizeof(byte));
//-128 到 127
Console.WriteLine("sbyte 占用:" + sizeof(sbyte));
Console.WriteLine("char 占用:" + sizeof(char));
//-79228162514264337593543950335 到 + 79228162514264337593543950335
Console.WriteLine("decimal 占用:" + sizeof(decimal));
//±5.0 × 10−324 到 ±1.7 × 10308 15-16 位
Console.WriteLine("double 占用:" + sizeof(double));
//±1.5 x 10−45 至 ±3.4 x 1038 7位
Console.WriteLine("float 占用:" + sizeof(float));
//-2,147,483,648 到 2,147,483,647 带符号的 32 位整数
Console.WriteLine("int 占用:" + sizeof(int));
//0 到 4,294,967,295 无符号的 32 位整数
Console.WriteLine("uint 占用:" + sizeof(uint));
//-9,223,372,036,854,775,808 到 9,223,372,036,854,775,807 64 位带符号整数
Console.WriteLine("long 占用:" + sizeof(long));
//0 到 18,446,744,073,709,551,615 无符号 64 位整数
Console.WriteLine("ulong 占用:" + sizeof(ulong));
//-32,768 到 32,767 有符号 16 位整数
Console.WriteLine("short 占用:" + sizeof(short));
//0 到 65,535 无符号 16 位整数
Console.WriteLine("ushort 占用:" + sizeof(ushort));
byte[] bytes = Encoding.UTF8.GetBytes("我们");
Console.WriteLine(Encoding.GetEncoding("gb2312").GetBytes("我们").Length);
Console.WriteLine(bytes.Length);
Console.ReadLine();
}
}
string占用的字节数和编码有关系，如果是UTF8则每个汉字占用3个字节，如果是gb2312则占用2个字节
2、而在实际的运行中，到底分配多少字节是和编译器有关系，来看一下c#生成好的EXE文件的IL代码：
static void Main()
{
int a8 = 8;
int a = 32;
Int16 a16 = 32767;
Int32 a32 = 2147483647;
Int64 a64 = 9223372036854775807;
Int64 aa64 = 8;
Int64 aaa64 = 32;
Console.WriteLine(a);
Console.WriteLine(a8);
Console.WriteLine(a16);
Console.WriteLine(a32);
Console.WriteLine(a64);
}
看一下IL代码：
.method private hidebysig static void Main() cil managed
{
.entrypoint
// Code size 75 (0x4b)
.maxstack 1
.locals init ([0] int32 a8,
[1] int32 a,
[2] int16 a16,
[3] int32 a32,
[4] int64 a64,
[5] int64 aa64,
[6] int64 aaa64)
IL_0000: nop
IL_0001: ldc.i4.8
IL_0002: stloc.0
IL_0003: ldc.i4.s 32
IL_0005: stloc.1
IL_0006: ldc.i4 0x7fff
IL_000b: stloc.2
IL_000c: ldc.i4 0x7fffffff
IL_0011: stloc.3
IL_0012: ldc.i8 0x7fffffffffffffff
IL_001b: stloc.s a64
IL_001d: ldc.i4.8
IL_001e: conv.i8
IL_001f: stloc.s aa64
IL_0021: ldc.i4.s 32
IL_0023: conv.i8
IL_0024: stloc.s aaa64
IL_0026: ldloc.1
IL_0027: call void [mscorlib]System.Console::WriteLine(int32)
IL_002c: nop
IL_002d: ldloc.0
IL_002e: call void [mscorlib]System.Console::WriteLine(int32)
IL_0033: nop
IL_0034: ldloc.2
IL_0035: call void [mscorlib]System.Console::WriteLine(int32)
IL_003a: nop
IL_003b: ldloc.3
IL_003c: call void [mscorlib]System.Console::WriteLine(int32)
IL_0041: nop
IL_0042: ldloc.s a64
IL_0044: call void [mscorlib]System.Console::WriteLine(int64)
IL_0049: nop
IL_004a: ret
} // end of method Program2::Main
可以看到，同样定义的是Int64的类型，1个是8，1个是32，1个是9223372036854775807
前两个都是4个字节：ldc.i4.8 ldc.i4.s
而后一个就是8个字节：ldc.i8