Let,
string a = “Test”;
string b = “test 2”;
string c = a + b
The output of c is "Testtest 2"
I would like to know how is the memory allocated?
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1dotnetperls.com/string-memoryshenku– shenku2013-04-09 06:38:03 +00:00Commented Apr 9, 2013 at 6:38
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1 Answer
string a = "Test";
You create a reference called a and its pointing to the "Test" object in memory.
string b = "test 2";
You create a reference called b and its pointing to the “test 2” object in memory.
string c = a + b;
You are allocating new memory address for a + b (and this process uses String.Concat method.) because strings are immutable in .NET. And then c reference assing to this new memory address.
Here is IL code of this;
IL_0000: nop
IL_0001: ldstr "Test"
IL_0006: stloc.0
IL_0007: ldstr "test 2"
IL_000c: stloc.1
IL_000d: ldloc.0
IL_000e: ldloc.1
IL_000f: call string [mscorlib]System.String::Concat(string,
string)
IL_0014: stloc.2
IL_0015: ldloc.2
stloc.0 is used, which stores the value on the top of the evaluation stack into the local memory slot 0.
ldstr instruction is used to load a string into the memory or evaluation stack. It is necessary to load values into evaluation stack before that can be utilized.
The ldloc instruction is a load local instruction. Ldloc places the value of a local variable on the stack.