66 lines
1.4 KiB
C
66 lines
1.4 KiB
C
// program to generate all permutation of the given string
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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//declare permutation and swap functions
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void permutation(char *,int,int);
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void swap(char *,char *);
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int main()
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{
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char *s;
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// dynamically creating string length
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s=(char*)malloc(sizeof(char)*1000);
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// getting string
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fgets(s,1000,stdin);
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// changing size to the length of string+1 to store null at end
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s=realloc(s,strlen(s)+1);
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//calling permutation
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permutation(s,0,strlen(s)-1);
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return 0;
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}
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void permutation(char *str,int s,int e)
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{ //declare variables
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static int count;
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int i;
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//base condition
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if(s==e)
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{
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count++;
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//Printing the string permutation's
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printf("%d(%s)\n",count,str);
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}
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else
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{
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for(i=s;i<=e;i++)
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{ //swapping variables value
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swap(str+s,str+i);
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//calling permutation function
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permutation(str,s+1,e);
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//now swap the variables value and make it before one
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swap(str+s,str+i);
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}
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}
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}
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//swap function
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void swap(char *a,char *b)
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{
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char temp;
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//putting value in temp
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temp=*a;
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// putting value in a pointer
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*a=*b;
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//now putting value of temp in b pointer
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*b=temp;
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//swapping done
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}
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// Example:
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//Input: abc
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//Output: 1(abc)
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// 2(acb)
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// 3(bac)
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// 4(bca)
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// 5(cba)
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// 6(cab)
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