Reverse Digits in C++

Reverse Digits in C++

• Vinod Anand

  Hi,
  that's not the right approach to the problem. Try writing the string from the last char to the begining to a new string.
  
  
  

• digitig

  I used this code, but I’m not sure it’s right or wrong (Left Shifting):

  //This is the wrong code, full of errors too :(< xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

  #include<iostream>

  using namespace std;

  void main () {

        int number,reverse;

        cout<<"Enter an integer digit: ";

        cin>>number;

        if (0<=number<=9){

              reverse=number<<1;

              cout<<"Reverse="<<reverse<<endl;

        }

        else if (9<number<=99); {

              reverse=number<<2;

              cout<<"Reverse="<<reverse<<endl;

        }

        else if (99<number<=999); {

              reverse=number<<3;

              cout<<"Reverse="<<reverse<<endl;

        }

        else if (999<number<=9999); {

              reverse=number<<4;

              cout<<"Reverse="<<reverse<<endl;

        }

   

        else if(9999<number<=65535); {

              reverse=number<<5;

              cout<<"Reverse="<<reverse<<endl;

        }

  }

  So Please I need help getting the right to do, heard I have to make something called swap or something like that to reverse digits. Please help me!!

  Ahmed Mahdy

  
  

• evaleah

  It is just a simple loop.

  int num = 1234;
  int ret = 0;

  while (num != 0) {
  int r = num % 10;
  ret = ret * 10 + r;
  num = num / 10;
  }

  printf("%d\n", ret);

  
  
  

• Penn Wallace

  Thank you so much for the code

  I just get this warning which bans pogram to be excuted

  warning C4700: uninitialized local variable 'strEntry' used

  Kind Regards ,

  Ahmed Mahdy

  
  

• Denis Ruckebusch

  Sorry my bad

  #include <iostream>

  using namespace std;

  void ret_str(char* s)

  {

  if(*s != '\0')

  ret_str(s+1);

  cout<<*(s);

  }

  int main()

  {

  cout << "Please write your string : " ;

  //255 is an arbitrary number it represents the length of your input string

  char strEntry[255];

  cin >> strEntry;

  ret_str(strEntry);

  return 0;

  }

  Hope it helps you !!!

  
  
  

• laks_win

  You might as well go all out and use recursion (an advanced C++ feature) also it's nice and short:

  http://code.dreamincode.net/snippet313.htm

  
  

• Checkup From the Neck Up

  Ted. wrote:

  You might as well go all out and use recursion (an advanced C++ feature) also it's nice and short: http://code.dreamincode.net/snippet313.htm

  Thank you so much for this answer . I just want a suggestion for code modification where user would enter an integer so that it could got reversed back and here is the code:

  #include <iostream>

  using namespace std;

  void ret_str(char* s)

  {

  if(*s != '\0')

  ret_str(s+1);

  cout<<*(s);

  }

  int main()

  {

  ret_str("123456");

  return 0;

  }

  
  

• HannesCoetzee

  #include <iostream>

  using namespace std;

  void ret_str(char* s)

  {

  if(*s != '\0')

  ret_str(s+1);

  cout<<*(s);

  }

  int main()

  {

  cout << "Please write your string : " ;

  char* strEntry;

  cin >> strEntry;

  ret_str(strEntry);

  return 0;

  }

  
  
  

• great_ghost

  n0n4m3 wrote:

  Hi, that's not the right approach to the problem. Try writing the string from the last char to the begining to a new string.

  How Please I need further help with a code!!

  I didn't study strings in college yet!!

  Regards,

  Ahmed Mahdy

  
  

• top.gun1

  This sounds like a homework assignment: you'll probably learn more and find people more willing to help you if you try to solve it yourself and then ask specific questions if you get stuck.
  
  

• gexaman

  Up, Help me!!
  
• Reverse Digits in C++