Using const char* Post: 302684181

Sponsored Content

Top Forums Programming Using const char* Post 302684181 by alister on Thursday 9th of August 2012 08:56:25 AM

08-09-2012

Registered User

Quote:

Originally Posted by kristinu

I want to know how it is that I can change desc when I declared desc as const.

You are mistaken. You have not declared desc as const. desc is a memory address and it can change. However, the char that the memory address points to cannot be modified through desc.

Read hergp's response carefully.

Since desc is not constant, you can assign a new memory address to it, which is what's happening with desc="string". What you cannot do (even if the memory is dynamically allocated) is indirect through desc to modify a character, *desc='a'.

Regards,
Alister

Last edited by alister; 08-09-2012 at 10:02 AM..

This User Gave Thanks to alister For This Post:

alister

View Public Profile for alister

Find all posts by alister

10 More Discussions You Might Find Interesting

1. Programming

Reference to a const

Can any one explain how the statement '2' in the following statements is a legal one. int & ref = 3; // Illegal statement - Compiler error. const int& ref=3 ; // Compile and executes properly. Thanks in Advance, Arun

2. Programming

diff b/w char const in C/C++

hi, what is the difference b/w char in C and C++.and give me the examples. Thanks... sarwan

3. UNIX for Dummies Questions & Answers

int open(const char *pathname, int flags, mode_t mode) doubt...

hello everybody! I want to create a file with permissions for read, write, and execute to everybody using C, so I write this code: #include <stdio.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> int main(){ int fileDescriptor; fileDescriptor =...

4. Programming

Adding a single char to a char pointer.

Hello, I'm trying to write a method which will return the extension of a file given the file's name, e.g. test.txt should return txt. I'm using C so am limited to char pointers and arrays. Here is the code as I have it: char* getext(char *file) { char *extension; int i, j;...

5. Programming

concat const char * with char *

hello everybody! i have aproblem! i dont know how to concatenate const char* with char const char *buffer; char *b; sprintf(b,"result.txt"); strcat(buffer,b); thanx in advance

6. Programming

Optional non-const reference argument c++ ?

Is it possible to have a non-const reference variable as an OPTIONAL/DEFAULT parameter to c++ function ex void read(string &data,int &type=0 /*or something*/) ; so i will call read(data); //or int type; read(data,type); printf("Type =%d",type); I found one dirty workaround ...

7. Programming

Questions about const

Hi all, I have some questions about functions. In a code I have (a .hpp file) there is this line which says: const Class_1_Name* Class_2_Name::MethodName(int ipart) const {return (ClassName*)_ref_to_method.At(ipart);} My questions are: What is the meaning of the two constants,...

8. Programming

Why this const variable is not changing even after applying const_cast?

Hi In the following code, why the variable 'i' still retains the value 10 instead of 11? Why it is not possible to alter this variable's value? int main() { const int i = 10; *(const_cast<int*>(&i)) = 11; cout << i << endl; // Ans: 10 }

9. Programming

error: invalid conversion from �const char� to �char�

Compiling xpp (The X Printing Panel) on SL6 (RHEL6 essentially): xpp.cxx: In constructor ‘printFiles::printFiles(int, char**, int&)’: xpp.cxx:200: error: invalid conversion from ‘const char*’ to ‘char*’ The same error with all c++ constructors - gcc 4.4.4. If anyone can throw any light on...

10. Programming

Double to const char conversion

Dear all, I am using C and ROOT for programming. And I need to incorporate following in my code. char *fps=NULL; int dec=0,sign=0; float mean = h1->GetMean(1); //0.001298 fps= fcvt(mean,6 , &dec, &sign); I need to provide this mean as const char to some other function to get...

10 More Discussions You Might Find Interesting

1. Programming

Reference to a const

Discussion started by: arun.viswanath

2. Programming

diff b/w char const in C/C++

Discussion started by: sarwan

3. UNIX for Dummies Questions & Answers

int open(const char *pathname, int flags, mode_t mode) doubt...

Discussion started by: csnmgeek

4. Programming

Adding a single char to a char pointer.

Discussion started by: pallak7

5. Programming

concat const char * with char *

Discussion started by: nicos

6. Programming

Optional non-const reference argument c++ ?

Discussion started by: johnbach

7. Programming

Questions about const

Discussion started by: eager2no

8. Programming

Why this const variable is not changing even after applying const_cast?

Discussion started by: royalibrahim

9. Programming

error: invalid conversion from �const char� to �char�

Discussion started by: GSO

10. Programming

Double to const char conversion

Discussion started by: emily