Write a C program generate permutations.

Iterative C program

#include <stdio.h>
#define SIZE 3
int main(char *argv[],int argc)
{
char list[3]={‘a’,’b’,’c’};
int i,j,k;

for(i=0;i<SIZE;i++)
for(j=0;j<SIZE;j++)
for(k=0;k<SIZE;k++)
if(i!=j && j!=k && i!=k)
printf(“%c%c%c\n”,list[i],list[j],list[k]);

return(0);
}

Recursive C program

#include <stdio.h>
#define N  5

int main(char *argv[],int argc)
{
char list[5]={‘a’,’b’,’c’,’d’,’e’};
permute(list,0,N);
return(0);
}

void permute(char list[],int k, int m)
{
int i;
char temp;

if(k==m)
{
/* PRINT A FROM k to m! */
for(i=0;i<N;i++){printf(“%c”,list[i]);}
printf(“\n”);
}
else
{
for(i=k;i<m;i++)
{
/* swap(a[i],a[m-1]); */
temp=list[i];
list[i]=list[m-1];
list[m-1]=temp;

permute(list,k,m-1);

/* swap(a[m-1],a[i]); */

temp=list[m-1];
list[m-1]=list[i];
list[i]=temp;
}
}
}

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s