Reversing a string

[maticode20]

A little help with my program please. I'm trying to print out an inputted string in reverse
----> John Cena = aneC nhoJ

void printReverse (string str)
{
    string reverseLetter [str.length()];//This string is suppose to contain the characters of str sorted in reverse.
    int r = 0;
    for (int n=str.length();n>=0; n--)  //Loop through each of the characters of str, from the last to the first.
    {
        str [n] = reverseLetter[r];     //Tried to assign the last value  of str to the first of reverseLetter.
        r++;
    }
    
}

[Naughty Albatross]

Hi,
Try this :

void printReverse (string str)
{
    string reserveStr;
    for (int i = str.length() - 1; i >= 0; i--)  reserveStr += str[i];
    cout << reserveStr;
}

[Naughty Albatross]

(Does that help you?) :)

[Naughty Albatross]

I edited my solution.
Now everything works fine.

[E0p9LyTq]

#include <iostream>
#include <string>
#include <cstdint>

int main ()
{
   std::string myString = "This is a sample string I will reverse";

   std::cout << "Printing the string forwards:\n";
   for (uint16_t loop = 0; loop < myString.size(); loop++)
   {
      std::cout << myString[loop];
   }

   std::cout << "\n\nPrinting the string backwards:\n";
   for (size_t loop = myString.size(); loop > 0; loop--)
   {
      std::cout << myString[loop - 1];
   }
   std::cout << "\n";
}

Printing the string forwards:
This is a sample string I will reverse

Printing the string backwards:
esrever lliw I gnirts elpmas a si sihT

[maticode20]

FurryGuy:
I wrote my code that way but what i was trying to do is to assign the reversed string to a new variable. Thank you anyways.



closed account 5a8Ym39o6:
Thank you, this works perfectly, would you be so kind to briefly explain how is it that it works?

Why do you use "str.length() -1"

And how does this work -> reserveStr += str[i];
I thought you had to use a string array so you were able to assign each character to an element.

[Naughty Albatross]

> Thank you, this works perfectly, would you be so kind to briefly explain how is it that it works?

string reserveStr;
This line creates an empty string.

for (int i = str.length() - 1; i >= 0; i--) reserveStr += str[i];

Appends a new character (str[i]) at the end of the reserveStr string every per loop.

[Naughty Albatross]

> Why do you use "str.length() - 1"
An array subscript starts at 0, and finishes at size - 1

And str.length() - 1 is equivalent to str.size() - 1

[maticode20]

Thank you very much, you are a genius

[Naughty Albatross]

Glad it helped :)

[E0p9LyTq]

@maticode20,

there is a function template, reverse(), in the <algorithm> header, if you don't need to create your own version:

#include <iostream>
#include <algorithm>
#include <string>

int main ()
{
   std::string myString = "This is a test string I will reverse";
   std::string reversed_string = myString;
   
   std::reverse(reversed_string.begin(), reversed_string.end());

   std::cout << myString << "\n" << reversed_string << "\n";
}

This is a test string I will reverse
esrever lliw I gnirts tset a si sihT

[Thomas1965]

Has nobody heard about reversed iterators ?

#include <iostream>
#include <string>

using namespace std;

int main ()
{
  string org = "Hello world.";
  string reversed (org.rbegin (), org.rend ());

  cout << "Reversed string: " << reversed << "\n\n";

  system ("pause");
  return 0;
}

[E0p9LyTq]

@Thomas1965, I was going to mention reversed iterators.

your code is much neater than what I had, using the constructor. Ooops!