simple program to find permutation of all letters of a word

[code2cplus]

a simple program to find out the permutations of all the letters in the word

ex:
abc gives

abc
acb
bac
bca
cba
cab

void swap(char *p,char *q){
char c;
c=*p;
*p=*q;
*q=c;
}



void perm(char *a,int m,int n)
{

   if(m==n){
for(int i=0;i<=n;i++)
  cout<<a[i];
    }

else
{
for(int j=n;j<=m;j++)
{
swap(a[j],a[n]);
perm(a,m,n+1);
swap(&a[j],&a[n]);
}

}



int main()
{
  char *a = "haia";
 perm(a,strlen(a)-1,0);
getch();
return 0;
}

[~s.o.s~]

Please my friend try ur code before posting it on the forum so that other ppl are not misled.

THe code u have posted doesnt work.

[roverphoenix]

dude

void swap(char *p,char *q) , thts the function def, how are you calling it
swap(a[j],a[n]);?? , the function expects a pointer not a chracter, no wonder it crashes

[binoy.jayan]

Hi friends... This works.. Try out..
Its the corrected one

#include<stdio.h>
#include<string.h>

   void swap(char *p,char *q)
   {
   char c;
   c=*p;
   *p=*q;
   *q=c;
   }
   
  void perm(char *a,int m,int n)
  {
	int i,j;
  	if(m==n)
  	{
  	for(i=0;i<=n;i++)
  		printf("%c", a[i]);
	printf("\n");
  	}
  	else
  	{  
  	for(j=n;j<=m;j++)
  	{
  		swap(&a[j],&a[n]);
 	 	perm(a,m,n+1);
  		swap(&a[j],&a[n]);
  	}
  	}
  }

  int main()
  {
  char *a = "hai";
  perm(a,strlen(a)-1,0);
  getch();
  return 0;
  }

[jephthah]

Hi friends... This works.. Try out..
Its the corrected one

so, when you say "works" ... you really mean "crashes with a fatal runtime error", right?

thanks for resurrecting a 4 year old thread to post your non-working crap code.

[Nick Evan]

so, when you say "works" ... you really mean "crashes with a fatal runtime error", right?

thanks for resurrecting a 4 year old thread to post your non-working crap code.

I guess it could be worse... The swap function uses a temp-var instead of the xor-swap for example?

[binoy.jayan]

Hi Jephthah, I appologize if the code I posted doesnt work.
I ran a few test cases and it was woking fine. Thats why I posted it.

[Solicko]

Guys, in strict C code you cant do char *a = "hai"; without first allocating the necessary memory for it. Either use malloc function, or change the line to : char a[3] = "hai";

[thejokerguy]

I put a[10] and removed calling second swap function.
It's Working! Thanks.But I didn't get the logic of this program.
Can somebody please explain?

#include<stdio.h>
#include<string.h>

   void swap(char *p,char *q)
   {
   char c;
   c=*p;
   *p=*q;
   *q=c;
   }
   
  void perm(char *a,int m,int n)
  {
	int i,j;
  	if(m==n)
  	{
  	for(i=0;i<=n;i++)
  		printf("%c", a[i]);
	printf("\n");
  	}
  	else
  	{  
  	for(j=n;j<=m;j++)
  	{
  		#include<stdio.h>
#include<string.h>

   void swap(char *p,char *q)
   {
   char c;
   c=*p;
   *p=*q;
   *q=c;
   }
   
  void perm(char *a,int m,int n)
  {
    int i,j;
      if(m==n)
      {
      for(i=0;i<=n;i++)
          printf("%c", a[i]);
    printf("\n");
      }
      else
      {  
      for(j=n;j<=m;j++)
      {
          swap(&a[j],&a[n]);
          perm(a,m,n+1);
          	[B]//swap(&a[j],&a[n]);[/B]
      }
      }
  }

  int main()
  {
  char a[10] = "swap";
  perm(a,strlen(a)-1,0);
  //getch();
  return 0;
  }
  		
  	}
  	}
  }

  int main()
  {
  char a[10] = "swap";
  perm(a,strlen(a)-1,0);
  //getch();
  return 0;
  }

[ragziraghu]

binoy.jayan's corrected code works fine.

[bharadwaj.p.s]

Hai can any one modify this code to produce the combination that will be able to pronounce? I mean if the input is abc then it should produce cab and bac only. not all of it.

[Mehdi_1]

this is my code

#include <stdio.h>
#include <string.h>
#include <conio.h>

int main(){
    char x[40],b;
    int i,j,l;
    puts("enter string :");
    gets(x);
    j = (strlen(x) -1)*strlen(x);
    i=0;
    l=0;
    for(i=0;i<j/2;i++){

        for(l=0;l<strlen(x)-1;l++){
            b = x[l];
            x[l] = x[l+1];
            x[l+1] = b;
            x[strlen(x)] = '\0';
            puts(x);
        }
    }
    getchar;
    return 0;
}

[Assembly Guy]

Hai can any one modify this code to produce the combination that will be able to pronounce? I mean if the input is abc then it should produce cab and bac only. not all of it.

To do this, you'd have to sit down and write out pairs (maybe even triplets) of letters which are pronouncable. You'd then have to create an array of these in your program and go from there... Unfortunately, it's not an overly easy or quick task.