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Concatination in StringBuilder

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Join Date: Nov 2007

Posts: 3

Reputation: varagpraveen is an unknown quantity at this point

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varagpraveen varagpraveen is offline

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Concatination in StringBuilder

Nov 21st, 2007

What is the difference in memory allocation and performance by using

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 C# Syntax (Toggle Plain Text) 
StringBuilder.Append("Str1");
StringBuilder.Append("Str2");
 
and 
 
StringBuilder.Append("Str1"+"Str2");
StringBuilder.Append("Str1");
StringBuilder.Append("Str2");

and 

StringBuilder.Append("Str1"+"Str2");

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Join Date: Apr 2007

Posts: 103

Reputation: mariocatch is an unknown quantity at this point

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mariocatch mariocatch is offline

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Re: Concatination in StringBuilder

Nov 21st, 2007

Ok, I wrote a little test application to time this because you got me interested.

Here's the calculation I used (based off your example).

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// Test single appends, going 10,000,000 times.
 for (int i = 0; i < 10000000; i++)
          _SB1.Append("Test");
// Test append + append going 5,000,000 times.
for (int i = 0; i < 10000000/2; i++)
          _SB2.Append("Test" + "Test");
// Test single appends, going 10,000,000 times.
 for (int i = 0; i < 10000000; i++)
          _SB1.Append("Test");
// Test append + append going 5,000,000 times.
for (int i = 0; i < 10000000/2; i++)
          _SB2.Append("Test" + "Test");

The results (in milliseconds):

First Case (single appends)
77ms
71ms
78ms
73ms

Second Case (Append w/ 2 String +'s)
48ms
61ms
57ms
57ms

So, going half the amount of times, doing the same amount of text, adding strings within an append call is quicker than doing multiple single appends.

Last edited by mariocatch; Nov 21st, 2007 at 10:38 pm.