Recursion program

[Nethra]

Hi , I need the program of reversing a number using recursion.
Ex: if input is 123435 , output to be 534321.

[sicarie]

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[faceboy]

yow thry this function

[palani12kumar]

Hi , I need the program of reversing a number using recursion.
Ex: if input is 123435 , output to be 534321.

try this:

i think it will give what you want....
all the best......

[sicarie]

faceboy & palani12kumar-

This is a site where we attempt to help people, however posting code answers is not permitted. The OP will not learn anything by merely using your code, it is much more beneficial to have them attempt it, and then help them fix that code they attempted. I have removed the code you have posted so others cannot copy it, and please do not directly post code unless it is required, or a modification of code that has been posted.

[Nethra]

Hi,
I have tried with this code

{
                    if (n == 0)
                          return;
                    else
                    {
                         digit = num % 10;
                         rev = rev * 0 + digit;
                         num = numrv(num / 10);
                     }
                   }

here numrv is the recurssive function.but for this i am getting only the last digit as output.

[Ganon11]

What is rev supposed to be doing? In your operation, you set

rev = rev * 0 + digit;

which is evaluated as

rev = (rev * 0) + digit --> rev = 0 + digit --> rev = digit;

[Motoma]

Pseudo code

function reverse(string)
{
    if(length(first(string)) == 1) return string;
    return reverse(butfirst(string)) + first(string);

/*
The first function returns the first character of the string
The length function returns the length of a string
The butfirst function returns the string without the first character.
*/
}

[Nethra]

 if (n == 0)
                          return;
                    else
                    {
                         digit = num % 10;
                         rev = rev * 10 + digit;
                         num = numrv(num / 10);
                         return rev;
                     }
                   }

actually that was 10 and not 0.I also missed the return statement.now i have mentioned the correct code.the logic here is ,
the digit variable get that last digit with mod operator which is mutiplied with 10 to push that digit to left side of the num.then the actual num is divided by 10 to remove the last digit.this continues until num becomes zero.

[Nethra]

Hi,
Sorry I didnot get the pseudocode provided above. my doubt is that should the address of the string be passed to the string parameter,what will be the defnition for first and butfirst function.Can the logic be provided in simple, please.

[Savage]

Hi,
Sorry I didnot get the pseudocode provided above. my doubt is that should the address of the string be passed to the string parameter,what will be the defnition for first and butfirst function.Can the logic be provided in simple, please.

Are u entering number as int or as array of chars(string)?

If you are entering as a int you need to convert it to array of chars.After that use
a recursion so that fisrt element becomes last.To do this you need to find the lenght using strlen and then something like this in function:

if(k<(strlen(number)-1)/2)
{
      temp=number[k],number[k]=number[strlen(number)-k],number[strlen(number)-k]=temp; // k will start as 0 and increase
      //call the function with k+1 argument.
}
return number;

Now,let us do a test:

1.

INPUT: number=12345;

strlen=5;

k=0,k<2,temp=nu mber[0],number[0]=number[4],number[4]=temp; (52341)
k=1,k<2,temp=nu mber[1],number[1]=number[3],number[3]=temp; (54321)

2.

INPUT: number=345678

strlen=6;

k=0;k<3,temp=nu mber[0],number[0]=number[5],number[5]=temp; (845673)
k=1,k<3,temp=nu mber[1],number[1]=number[4],number[4]=temp; (875643)
k=2,k<3,temp=nu mber[2],number[2]=number[3],number[3]=temp; (876543)

As we can see it works now is up to you to create such a function.

Savage

[metalgod4eva]

Here is a great example of recursion without using any input and still have 12344321 as an output. This doesn't give it away nor will it work on your input variable but its a great way to break down recusion programs and theorize how to acomplish your goal.

#include <stdio.h>
int factorial (int x)
{
        printf("%d",x);
       if(x < 5){
       factorial(x+1)
       }
      printf("%d",x);
}

int main()
{
int x =1;
factorial(x);
getchar();
}

[Nethra]

HI,
Thanks,I got program with logic.

[Nethra]

Can any one say be how to store the information in bits.

For ex,the program- store the VIBGYOR color info in bits.When the given input is a number the output should give which bits indicate the color.

Thanks in Advance.

[Nethra]

Can any one say how to store the information in bits.

For ex,the program- store the VIBGYOR color info in bits.When the given input is a number the output should give which bits indicate the color.

Thanks in Advance