Is there a better way to permutate a string?

Q: Write a function to print all of the permutations of a string.

A: I wrote a recursive function to fulfill this. I was wondering if there's a better way to do this? either simpler or having less Runtime...
Thanks!

Code:

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#include <string.h>
#include <iostream.h>
/*Remove one character from str*/
void strrmv(const char *str, char* newstr,int removethis)
{       
        for (int i=0; i<removethis; i++){
                *(newstr+i)=*(str+i);
        }
        for(int i=removethis+1; i<strlen(str); i++){
                *(newstr+i-1)=*(str+i);
        }
        *(newstr+i-1)='\0';       
}

void permuString(char *a, int size)
{       
       
        if (size==1){
                cout<<a<<endl;
                return;
        }
        else
        {
                for (int i=0; i<size; i++)
                {
                        cout << a[i];
                        char *temp= new char[size];
                        strrmv(a,temp,i);
                        permuString(temp, size-1);       
                        delete temp;
                }
        }
}



void main()
{       
        char instr[]="abcd";
        int l = strlen(instr);
        permuString(instr,l);
}

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//p.s.: what's the best way to create an array dynamicly according to the input? Should I use new, delete? or should I use vector?

Check the msnd online please, I think there is something similar for you to take alook at. It is nice also:D




Best Regards,:)

Quote:

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Originally posted by erxuan
Q: Write a function to print all of the permutations of a string.

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You mean this?

Code:

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#include <iostream>
#include <algorithm>
#include <cstring>

using namespace std;

void PrintPermutation(char *p)
{
    cout << p << endl;
    int nLen = strlen(p);
    while (next_permutation(p, p + nLen))
            cout << p << endl;
}

int main()
{
    char p[] = "ABC123";
    PrintPermutation(p);
    return 0;
}

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If you're wondering, next_permutation() is an STL <algorithm> function that does what you want.

Regards,

Paul McKenzie