'C' question

[newguy]

Hi all !
Does anyone know how to generate all possible permutations for, lets say 5 / 6 letters of the alphabet( user is told to input a word), while converting to lowercase?
Thanks !!

[quzah]

Yep. Sure do.

Now that we all know that I can do it, how about you post some of your code so we can see if you can do it.

Quzah.

[C_Coder]

What Quzah means is try and have a go yourself, you'll learn a lot faster and if you still can't do it post what code you have and we'll tell you where you're going wrong.

[newguy]

ok.. first of all, i'm a newbie at C. I've got some sample code which did permutations for NUMBERS, not alphabets. I made some changes to it. There're many errors in the code listed below. Need to know what to do to make that change. Thanks !



int n;
int i;
char letters; /* The permutation */

void PrintPerm() {

static const char *letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
for (i=0; i <= n; i++)
printf( "%c", a[i] );
printf("\n");
}

void swap(char [i], char [j])
{

int temp;
temp = a[i];
a[i] = a[j];
a[j] = temp;
}

int Next() {

int k,j,r,s;

k = n-1;
while (a[k] > a[k+1]) k--;
if (k == 0) return(0);
else {
j = n;
while (a[k] > a[j]) j--;
swap(j,k);
r = n; s = k+1;
while (r>s) {
swap(r,s);
r--; s++;
}
}
PrintPerm();
return(1);
}

void main () {

int i;

printf( "Enter a 5 / 6 letter word: " );
scanf( "%c", &n );

if (n<= i[0]) exit(1);

printf( "\n" );
for (i=[0]; i<=[n]; ++i) {
a[i] = i;
}
PrintPerm();
while (Next());
printf( "\n" );
}

[newguy]

anyone??

[Stoned_Coder]

one way of doing this is to use nested loops.
i.e.

for(char i='a';i<='z';i++)
for(char j='a';j<='z';j++)
for(char k='a';k<='z';k++)
printf("%c%c%c\t",i,j,k);

will do perms of 3 letters.

[newguy]

This is a very simplified version of the main body of my program. Can't get it to compile. Any thoughts? Pls reply as soon as you can. THANKS !!

#include <stdio.h>
#include <stdlib.h>

main()
{
char first;
char second;
char third;
char forth;
char fifth;
char alphabets;


static constant char alphabets [25]= {'A','B','C','D','E','F','G','H','I','J','K','L',' M','N','O','P','Q','R','S','T','U','V','W','X','Y' ,'Z'};
printf(" Enter a 5 letter word, with no spaces in between ");
scanf("%c%c%c%c%c", &first,&second,&third,&forth,&fifth);
{
for(char first ='A';first<='Z'; first++)
for(char second ='A';second<='Z'; second++)
for(char third ='A';third<='Z'; third++)
for(char third ='A';forth<='Z'; forth++)
for(char third ='A';fifth<='Z'; fifth++)
;
}

printf("%c%c%c%c%c\t",first,second,third,forth,fif th);
printf("\n");
return 0;

}

[Stoned_Coder]

The way i showed you wont work for user input. In that case you can still use nested loops but the idea is to use them to cycle through the elements of the inputted string. i.e. for a five letter word to print all the chars in all poss orders then use five nested loops each counting from 0 to 4 then at the heart of the loops you need a printf statement like ....

printf("%c%c%c%c%c\n",mystring[i],mystring[j],mystring[k],mystring[l],mystring[m]);

You will probably be better using tabs instead of newlines to space with.

[newguy]

how would you define and initialize mystring ? This is the code I have so far, including mystring. Pls feel free to adjust the code
Thanks

#include <stdio.h>
#include <stdlib.h>

main()
{
char first;
char second;
char third;
char forth;
char fifth;
char alphabets;


static const char alphabets [27]= {'A','B','C','D','E','F','G','H','I','J','K','L',' M','N','O','P','Q','R','S','T','U','V','W','X','Y' ,'Z'};
printf(" Enter a 5 letter word, with no spaces in between ");
scanf("%c%c%c%c%c", &first,&second,&third,&forth,&fifth);
{
for(char first ='A';first<='Z'; first++)
{
printf("%c%c%c%c%c\n" ,mystring[first],mystring[second],mystring[third],mystring[forth],mystring[fifth]);
}
for(char second ='A';second<='Z'; second++)
{
printf("%c%c%c%c%c\n" ,mystring[first],mystring[second],mystring[third],mystring[forth],mystring[fifth]);
}
for(char third ='A';third<='Z'; third++)
{
printf("%c%c%c%c%c\n" ,mystring[first],mystring[second],mystring[third],mystring[forth],mystring[fifth]);
}
for(char third ='A';forth<='Z'; forth++)
{
printf("%c%c%c%c%c\n" ,mystring[first],mystring[second],mystring[third],mystring[forth],mystring[fifth]);
}

for(char third ='A';fifth<='Z'; fifth++)
{
printf("%c%c%c%c%c\n" ,mystring[first],mystring[second],mystring[third],mystring[forth],mystring[fifth]);
}

char first = tolower(first);
char second = tolower(second);
char third = tolower(third);
char forth = tolower(forth);
char fifth = tolower(fifth);
;
}

printf("%c%c%c%c%c\t",first,second,third,forth,fif th);
printf("\n");
return 0;

}

[Stoned_Coder]

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

char* newgets(char* buffer,int num)
{
int i;
fgets(buffer,num,stdin);
i=strlen(buffer)-1;
if (buffer[i]=='\n') buffer[i]='\0';
return buffer;
}

int main()
{
int i,j,k,l,m;
char buffer [6];
printf("Enter a five letter word ?");
newgets(buffer,6);
printf("\nYou entered %s\n",buffer);
printf("Possible perms are :-  ");
for(i=0;i<5;i++)
for(j=0;j<5;j++)
for(k=0;k<5;k++)
for(l=0;l<5;l++)
for(m=0;m<5;m++)
printf("%c%c%c%c%c\t\t",buffer[i],buffer[j],buffer[k],buffer[l],buffer[m]);
return 0;
}

Its really that simple!

[newguy]

thanks stoned. you helped a lot. But how do you convert all letters to lowercase?. I tied toLower(). didn't work. Pls advise

[incognito]

well I am really a begginer to C but I do know how to do that,

declare a variable
int caps2lowercase='A'-'a';// or 'a'-'A'; for viceversa
if you don't know how to use it, how to get the values from the string reply and I'll help you.

[quzah]

variable = tolower( variable );

You cannot do: variable = 'A'-'a'; and then: variable = 'a'-'A'; to convert back. It doesn't work that way.

Quzah.

[incognito]

no I know I am just saying in case he wantst to get the other one just subtitute the codes.

[newguy]

Originally posted by elchulo2002
no I know I am just saying in case he wantst to get the other one just subtitute the codes.

actually, its just to convert all letters, regardless of uppercase or lowercase, to LOWERCASE. Need something to identify when the use input is uppercase and subsequently convert it to lowercase. Will a while Loop work?