Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

why the original string is getting changed

Posted on 2004-10-12
1
Medium Priority
?
207 Views
Last Modified: 2010-04-01
In the following code , I wanted to print the reverse of a string which was to be stored in an another string without affecting the original string. I made the following function. But it is affecting the original string also. Please let me know what's wrong
____________________________________________________
#include "iostream"
#include "string"

using namespace std;


char * reverse (char b[]);

void main()

{

      char a1[]="howyoudoing";
      
      char *game=reverse(a1);

      cout << game <<endl;

      cout << a1 <<endl;

}


char * reverse (char b[])

{

      int len=strlen(b);

      char *temp=new char[len];

      temp=b;

      for (int i=0; i<len/2;i++)
      {
      
            char x=temp[i];
            temp[i]=temp[len-i-1];
            temp[len-i-1]=x;
      }

      

      return temp;

}
0
Comment
Question by:anshuma
1 Comment
 
LVL 2

Accepted Solution

by:
bcsonka earned 500 total points
ID: 12294084
Hi,

In C++, when calling a function or procedure that contains an array as a parameter, the array is always passed by reference, not by value.  In the reverse() function, you are assigning the pointer to temp to the same memory location as that pointed to by b, and b is pointing to the same memory location as the original string, a1.  Thus when modifying temp, you are also modifying a1.

Instead of temp=b; in reverse(), try strcpy(temp, b); instead.

I hope that helps.
0

Featured Post

Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Article by: SunnyDark
This article's goal is to present you with an easy to use XML wrapper for C++ and also present some interesting techniques that you might use with MS C++. The reason I built this class is to ease the pain of using XML files with C++, since there is…
Basic understanding on "OO- Object Orientation" is needed for designing a logical solution to solve a problem. Basic OOAD is a prerequisite for a coder to ensure that they follow the basic design of OO. This would help developers to understand the b…
The viewer will learn how to use the return statement in functions in C++. The video will also teach the user how to pass data to a function and have the function return data back for further processing.
The viewer will be introduced to the technique of using vectors in C++. The video will cover how to define a vector, store values in the vector and retrieve data from the values stored in the vector.

926 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question