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Extension Methods to Reverse a String and StringBuilder Object

, 1 Jan 2011 CPOL
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Less code, and much faster, would be:public static string ReverseSB(string text) { int len = text.Length; if (len>1) { StringBuilder sb=new StringBuilder(text); int pivotPos=len/2; len--; for (int i = 0; i < pivotPos; i++) { int...
Less code, and much faster, would be:
 
public static string ReverseSB(string text) {
    int len = text.Length;
    if (len>1) {
        StringBuilder sb=new StringBuilder(text);
        int pivotPos=len/2;
        len--;
        for (int i = 0; i < pivotPos; i++) {
            int j=len-i;
            char temp=sb[i];
            sb[i]=sb[j];
            sb[j]=temp;
        }
        text=sb.ToString();
    }
    return text;
}
 

or its extension-method variant. Tested on a 80-char string it is 8 times faster. The reason should be clear: John's code creates 6 strings for each character pair, as each SubString, Remove, Insert method generates a new string object, copying the relevant characters.
 
Smile | :)

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This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Luc Pattyn
Software Developer (Senior) Perceler
Belgium Belgium
I am an engineer with a background in electronics, software and mathematics.
 
I develop technical software, both for embedded systems and for desktop equipment. This includes operating systems, communication software, local networks, image processing, machine control, automation, etc.
 
I have been using all kinds of microcontrollers and microprocessors (Intel 4004/8080/8051/80386/Pentium, Motorola 680x/680x0/ColdFire/PowerPC, Microchip PIC, Altera NIOS, and many more), lots of programming languages (all relevant assemblers, Fortran, Basic, C, Java, C#, and many more), and different operating systems (both proprietary and commercial).
 
For desktop applications and general development tools I have been using both UNIX systems and Mac/MacOS for many years, but I have switched to x86-based PCs with Windows, Visual Studio and the .NET Framework several years ago.
 
I specialize in:
- cross-platform development (making software that runs on diverse hardware/OS combinations)
- instruction set simulation
- improving software performance, i.e. making sure the software runs the job at hand in as short a time as possible on the given hardware. This entails algorithm selection, implementation design, accurate measurements, code optimisation, and sometimes implementing virtual machines, applying SIMD technology (such as MMX/SSE), and more.

Comments and Discussions

 
GeneralAhh yes, you most certainly did. :) PinmvpJohn Simmons / outlaw programmer1-Jan-11 6:45 
GeneralI did in the line <code>len--;</code> PinmvpLuc Pattyn1-Jan-11 6:26 
GeneralIn yours, j will create an exception on the first character ... PinmvpJohn Simmons / outlaw programmer1-Jan-11 6:11 

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