switch statement
/csbook/solutions/06/A03.cs
using System;
class Test {
static int DaysOf(int month) {
int days;
switch (month) {
case 1: case 3: case 5: case 7: case 8: case 10: case 12:
days = 31; break;
case 4: case 6: case 9: case 11:
days = 30; break;
case 2:
days = 28; break;
default:
days = 0; break;
}
return days;
}
static int DaysOf1(string month) {
int days;
switch (month) {
case "Jan": case "Mar": case "May": case "Jul": case "Aug": case "Oct": case "Dec":
days = 31; break;
case "Apr": case "Jun": case "Sep": case "Nov":
days = 30; break;
case "Feb":
days = 28; break;
default:
days = 0; break;
}
return days;
}
public static void Main() {
Console.WriteLine(DaysOf(7));
Console.WriteLine(DaysOf1("Oct"));
}
}
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CIL-Code of DaysOf:
.method private hidebysig static int32 DaysOf(int32 month) cil managed
{
// Code size 85 (0x55)
.maxstack 2
.locals init (int32 V_0,
int32 V_1,
int32 V_2)
IL_0000: ldarg.0
IL_0001: stloc.2
IL_0002: ldloc.2
IL_0003: ldc.i4.1
IL_0004: sub
IL_0005: switch (
IL_003c,
IL_0046,
IL_003c,
IL_0041,
IL_003c,
IL_0041,
IL_003c,
IL_003c,
IL_0041,
IL_003c,
IL_0041,
IL_003c)
IL_003a: br.s IL_004b
IL_003c: ldc.i4.s 31
IL_003e: stloc.0
IL_003f: br.s IL_004f
IL_0041: ldc.i4.s 30
IL_0043: stloc.0
IL_0044: br.s IL_004f
IL_0046: ldc.i4.s 28
IL_0048: stloc.0
IL_0049: br.s IL_004f
IL_004b: ldc.i4.0
IL_004c: stloc.0
IL_004d: br.s IL_004f
IL_004f: ldloc.0
IL_0050: stloc.1
IL_0051: br.s IL_0053
IL_0053: ldloc.1
IL_0054: ret
} // end of method Test::DaysOf
CIL-Code of DaysOf1:
.method private hidebysig static int32 DaysOf1(string month) cil managed
{
// Code size 347 (0x15b)
.maxstack 4
.locals init (int32 V_0,
int32 V_1,
object V_2)
IL_0000: volatile.
IL_0002: ldsfld class [mscorlib]System.Collections.Hashtable ''::'$$method0x6000002-1'
IL_0007: brtrue IL_00ee
IL_000c: ldc.i4.s 26
IL_000e: ldc.r4 0.5
IL_0013: newobj instance void [mscorlib]System.Collections.Hashtable::.ctor(int32,
float32)
IL_0018: dup
IL_0019: ldstr "Jan"
IL_001e: ldc.i4.0
IL_001f: box [mscorlib]System.Int32
IL_0024: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_0029: dup
IL_002a: ldstr "Mar"
IL_002f: ldc.i4.1
IL_0030: box [mscorlib]System.Int32
IL_0035: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_003a: dup
IL_003b: ldstr "May"
IL_0040: ldc.i4.2
IL_0041: box [mscorlib]System.Int32
IL_0046: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_004b: dup
IL_004c: ldstr "Jul"
IL_0051: ldc.i4.3
IL_0052: box [mscorlib]System.Int32
IL_0057: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_005c: dup
IL_005d: ldstr "Aug"
IL_0062: ldc.i4.4
IL_0063: box [mscorlib]System.Int32
IL_0068: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_006d: dup
IL_006e: ldstr "Oct"
IL_0073: ldc.i4.5
IL_0074: box [mscorlib]System.Int32
IL_0079: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_007e: dup
IL_007f: ldstr "Dec"
IL_0084: ldc.i4.6
IL_0085: box [mscorlib]System.Int32
IL_008a: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_008f: dup
IL_0090: ldstr "Apr"
IL_0095: ldc.i4.7
IL_0096: box [mscorlib]System.Int32
IL_009b: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_00a0: dup
IL_00a1: ldstr "Jun"
IL_00a6: ldc.i4.8
IL_00a7: box [mscorlib]System.Int32
IL_00ac: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_00b1: dup
IL_00b2: ldstr "Sep"
IL_00b7: ldc.i4.s 9
IL_00b9: box [mscorlib]System.Int32
IL_00be: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_00c3: dup
IL_00c4: ldstr "Nov"
IL_00c9: ldc.i4.s 10
IL_00cb: box [mscorlib]System.Int32
IL_00d0: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_00d5: dup
IL_00d6: ldstr "Feb"
IL_00db: ldc.i4.s 11
IL_00dd: box [mscorlib]System.Int32
IL_00e2: call instance void [mscorlib]System.Collections.Hashtable::Add(object,
object)
IL_00e7: volatile.
IL_00e9: stsfld class [mscorlib]System.Collections.Hashtable ''::'$$method0x6000002-1'
IL_00ee: ldarg.0
IL_00ef: dup
IL_00f0: stloc.2
IL_00f1: brfalse.s IL_0151
IL_00f3: volatile.
IL_00f5: ldsfld class [mscorlib]System.Collections.Hashtable ''::'$$method0x6000002-1'
IL_00fa: ldloc.2
IL_00fb: call instance object [mscorlib]System.Collections.Hashtable::get_Item(object)
IL_0100: dup
IL_0101: stloc.2
IL_0102: brfalse.s IL_0151
IL_0104: ldloc.2
IL_0105: unbox [mscorlib]System.Int32
IL_010a: ldind.i4
IL_010b: switch (
IL_0142,
IL_0142,
IL_0142,
IL_0142,
IL_0142,
IL_0142,
IL_0142,
IL_0147,
IL_0147,
IL_0147,
IL_0147,
IL_014c)
IL_0140: br.s IL_0151
IL_0142: ldc.i4.s 31
IL_0144: stloc.0
IL_0145: br.s IL_0155
IL_0147: ldc.i4.s 30
IL_0149: stloc.0
IL_014a: br.s IL_0155
IL_014c: ldc.i4.s 28
IL_014e: stloc.0
IL_014f: br.s IL_0155
IL_0151: ldc.i4.0
IL_0152: stloc.0
IL_0153: br.s IL_0155
IL_0155: ldloc.0
IL_0156: stloc.1
IL_0157: br.s IL_0159
IL_0159: ldloc.1
IL_015a: ret
} // end of method Test::DaysOf1
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