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I have seen people use a couple of different way of initializing arrays:
string[] Meal = new string[]{"Roast beef", "Salami", "Turkey", "Ham", "Pastrami"};
or another way, also called initializing is:
string[] Meats = {"Roast beef", "Salami", "Turkey", "Ham", "Pastrami" };
What is the best way, and what is the major difference between both ways (including memory allocation)?
466
Declaration tells the compiler about the existence of an entity in the program and its location. When you declare a variable, you should also initialize it. Initialization is the process of assigning a value to the Variable. Every programming language has its own method of initializing the variable.
Declaration: Variable is registered using a given name within the corresponding scope (e.g., inside a function). Initialization: When you declare a variable it is automatically initialized, which means memory is allocated for the variable by the JavaScript engine.
Notice that a variable that is not initialized does not have a defined value, hence it cannot be used until it is assigned such a value. If the variable has been declared but not initialized, we can use an assignment statement to assign it a value.
To initialize a variable is to give it a correct initial value. It's so important to do this that Java either initializes a variable for you, or it indicates an error has occurred, telling you to initialize a variable.
There is no difference in both cases. Compiler generates the same bytecode (newarr OpCode):
public static void Main()
{
string[] Meal = new string[] { "Roast beef", "Salami", "Turkey", "Ham", "Pastrami"};
string[] Meats = { "Roast beef", "Salami", "Turkey", "Ham", "Pastrami" };
}
MSIL:
.entrypoint
// Code size 100 (0x64)
.maxstack 3
.locals init ([0] string[] Meal,
[1] string[] Meats,
[2] string[] CS$0$0000)
IL_0000: nop
IL_0001: ldc.i4.5
IL_0002: newarr [mscorlib]System.String
IL_0007: stloc.2
IL_0008: ldloc.2
IL_0009: ldc.i4.0
IL_000a: ldstr "Roast beef"
IL_000f: stelem.ref
IL_0010: ldloc.2
IL_0011: ldc.i4.1
IL_0012: ldstr "Salami"
IL_0017: stelem.ref
IL_0018: ldloc.2
IL_0019: ldc.i4.2
IL_001a: ldstr "Turkey"
IL_001f: stelem.ref
IL_0020: ldloc.2
IL_0021: ldc.i4.3
IL_0022: ldstr "Ham"
IL_0027: stelem.ref
IL_0028: ldloc.2
IL_0029: ldc.i4.4
IL_002a: ldstr "Pastrami"
IL_002f: stelem.ref
IL_0030: ldloc.2
IL_0031: stloc.0
IL_0032: ldc.i4.5
IL_0033: newarr [mscorlib]System.String
IL_0038: stloc.2
IL_0039: ldloc.2
IL_003a: ldc.i4.0
IL_003b: ldstr "Roast beef"
IL_0040: stelem.ref
IL_0041: ldloc.2
IL_0042: ldc.i4.1
IL_0043: ldstr "Salami"
IL_0048: stelem.ref
IL_0049: ldloc.2
IL_004a: ldc.i4.2
IL_004b: ldstr "Turkey"
IL_0050: stelem.ref
IL_0051: ldloc.2
IL_0052: ldc.i4.3
IL_0053: ldstr "Ham"
IL_0058: stelem.ref
IL_0059: ldloc.2
IL_005a: ldc.i4.4
IL_005b: ldstr "Pastrami"
IL_0060: stelem.ref
IL_0061: ldloc.2
IL_0062: stloc.1
IL_0063: ret
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