Write a C++ program to reverse a string.


動機:
對於給你一個字串,
再要求你寫個function去reverse它,
要如何寫呢?!

說明:
利用 Dev-C++ 免費軟體,
再撰寫相關的程式即可達到要求, 程式碼如下:
(若重點是要求 algorithm 及 performance 的話,
可能程式碼就要另外思考如何改變了)


#include <cstdlib>
#include <iostream>

using namespace std;

static char str[] = "I am a good boy";

int reverse(int pos)
{
    // Here I am calculating strlen(str) everytime. 
    // This can be avoided by doing this computation
    // earlier and storing it somewhere for later use.
    if(pos < (strlen(str) / 2))
    {
        char ch;

        // Swap str[pos] and str[strlen(str) - pos - 1]
        ch = str[pos];
        str[pos] = str[strlen(str) - pos - 1];
        str[strlen(str) - pos - 1] = ch;

        // Now recurse!
        reverse(pos + 1);
    }
}

int main(int argc, char *argv[])
{
    printf("\nOriginal string : [%s]", str);

    // Call the recursion function
    reverse(0);

    printf("\nReversed string : [%s]\n", str);

    system("PAUSE");
    return EXIT_SUCCESS;
}

參攷: Write a C program to reverse a string.

執行檔下載連結: https://docs.google.com/leaf?id=0B_4eUrknq7N1NGY0N2Y2ZDQtMjYzYy00MzZjLTgxZTMtOTQ5MzM5YTUwMjk4&hl=zh_TW

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