Ambiguity in operator [] Post: 302530190

Sponsored Content

Top Forums Programming Ambiguity in operator [] Post 302530190 by 14341 on Monday 13th of June 2011 09:39:30 AM

06-13-2011

Registered User

Ambiguity in operator []

Hi All,

When i try to compile the following code for 64-bit it works, whereas for 32-bit version, Compiler barfs:

Code:

#include <iostream>
#include <string>

class String {
  public:
    String() { }
    String(const char* src) : myStr(src) { }
    String(const std::string& src) : myStr(src) { }
    String(const String& src) : myStr(src.myStr) { }

    operator const char*() const         { return myStr.c_str(); }
    char& operator[](size_t index)       { return myStr[index]; }
    char operator[] (size_t index) const { return myStr[index]; }

    size_t length() const { return myStr.length(); }
  private:
    std::string myStr;
};

int main() {
    String s("abcd");

    char c = s[1];

    std::cout << c << std::endl;

    return 0;
}

Code:

$ g++ -m32 -Wall -g ambiguous.cc
ambiguous.cc: In function ‘int main()’:
ambiguous.cc:23: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
ambiguous.cc:12: note: candidate 1: char& String::operator[](size_t)
ambiguous.cc:23: note: candidate 2: operator[](const char*, int) <built-in>

$ g++ -Wall -g ambiguous.cc
$./a.out
b

1) I cannot modify all the instances like, c = s[1]. There are hundreds of similar things in code.
2) operator const char* is required.

Could someone suggest any work-around, considering the above 2 points.

Thanks,
14341

---------- Post updated at 08:39 AM ---------- Previous update was at 08:38 AM ----------

Hi All,

Overloading the operator[], for all integer types (unsigned/signed) (int; long; long long) solved the problem.

Cheers,
14341

14341

View Public Profile for 14341

Find all posts by 14341

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

And operator

I am trying to check two variables and if both are blank I want to set a flag: the_f3_pid=`rsh $target ps -ef | grep "f3.eab" | awk '{print $2}'` the_f7_pid=`rsh $target ps -ef | grep "f7.eab" | awk '{print $2}'` if ; then y=1 fi I get an error: ./script_name: test: 0403-021 ]...

2. HP-UX

Or operator with if

hi, i was trying to club to test condition with if. if -o ; then it is giving me error message, i wanted to ask how can we check two condtions with one if.

3. Programming

ambiguity in program output

1 #include <fcntl.h> 2 3 main(int argc, char *argv) 4 { 5 char buf; 6 int fd, count = 0; 7 8 if (argc > 1) 9 fd = open(argv, O_RDONLY); 10 else 11 fd = 0; /* Use standard input */ 12 13 while (read(fd, buf, 1) > 0) { 14 if (count < 5) write(1, buf, 1); 15 ...

4. AIX

Fs space ambiguity

Hi All, I found a strange thing in one of our DB server. one of the file system /orcale/ABC/rman size df output showing 100% full eventhough its occupying 2.18MB $ df -mP /oraclev/ABC/rman Filesystem MB blocks Used Available Capacity Mounted on /dev/lv20906 1024.00 1024.00 0.00 100%...

5. Programming

new operator

Hi, Please clear the 2 questions, 2 Questions, 1) Why the new as a operator? Is there any special reason why it can't be a function like malloc? 2) How are we considering sizeof(),new are as a opearartors? I know + - * / -> , . etc.. are operators, which criteria satisfied by sizeof()...

6. Shell Programming and Scripting

Ambiguity in unicode, Perl CGI

Hello, I was written a cgi with a textarea to save some words from web. I grab and write words like this: $cgiparams{'CONTENTS'} =~ s/\r//g; #$cgiparams{'CONTENTS'} =~ s/�/á/g; open(TM, ">$editedfilename"); #binmode(TM,...

7. UNIX for Dummies Questions & Answers

su with << operator

All, THe below is my script , when i use this i am getting nothing . could any one help me to know what is the use of the << operator below su - $8 << supo echo "exportsph $2 $1 $3 $4" exportsph $2 $1 $3 $4 supo i also tried as individual command su - userid << supo , when i do...

8. Shell Programming and Scripting

equal to operator

Hi, I have the below script executed arg="dir" if "$arg" = "dir" then echo "true" else echo "false" fi Please let me know what happens in the if command. My output is: dir: dir: No such file or directory false which is not the desired output. When i used test command...

9. UNIX for Dummies Questions & Answers

+= operator

im new to bash scripting and im just using online tutorials and trial and error. i wanted to write a script to read numbers from a file and find their sum: #!/bin/bash theSum=0 for line in $(cat numbers.txt) do let "theSum = theSum + $line" echo "$line" done echo "The sum is...

10. Programming

Difference in multiple inheritance and multilevel inheritance: same method name ambiguity problem

Hi, In multi-level inheritance: class A { public: void fun() { cout << "A" << endl; } }; class B : public A { public: void fun() { cout << "A" << endl; } }; class C : public B { }; int main() { C c; c.fun(); // Ans: A }

LEARN ABOUT SUSE

string

STRING(3)						     Linux Programmer's Manual							 STRING(3)

NAME

       stpcpy, strcasecmp, strcat, strchr, strcmp, strcoll, strcpy, strcspn, strdup, strfry, strlen, strncat, strncmp, strncpy, strncasecmp, strp-
       brk, strrchr, strsep, strspn, strstr, strtok, strxfrm, index, rindex - string operations

SYNOPSIS

       #include <strings.h>

       int strcasecmp(const char *s1, const char *s2);

       int strncasecmp(const char *s1, const char *s2, size_t n);

       char *index(const char *s, int c);

       char *rindex(const char *s, int c);

       #include <string.h>

       char *stpcpy(char *dest, const char *src);

       char *strcat(char *dest, const char *src);

       char *strchr(const char *s, int c);

       int strcmp(const char *s1, const char *s2);

       int strcoll(const char *s1, const char *s2);

       char *strcpy(char *dest, const char *src);

       size_t strcspn(const char *s, const char *reject);

       char *strdup(const char *s);

       char *strfry(char *string);

       size_t strlen(const char *s);

       char *strncat(char *dest, const char *src, size_t n);

       int strncmp(const char *s1, const char *s2, size_t n);

       char *strncpy(char *dest, const char *src, size_t n);

       char *strpbrk(const char *s, const char *accept);

       char *strrchr(const char *s, int c);

       char *strsep(char **stringp, const char *delim);

       size_t strspn(const char *s, const char *accept);

       char *strstr(const char *haystack, const char *needle);

       char *strtok(char *s, const char *delim);

       size_t strxfrm(char *dest, const char *src, size_t n);

DESCRIPTION

       The string functions perform string operations on null-terminated strings.  See the individual man pages for descriptions of each function.

SEE ALSO

       index(3), rindex(3), strcasecmp(3), stpcpy(3), strcat(3), strchr(3), strcmp(3), strcoll(3), strcpy(3),  strcspn(3),  strdup(3),	strfry(3),
       strlen(3),  strncasecmp(3),  strncat(3),  strncmp(3),  strncpy(3),  strpbrk(3),	strrchr(3),  strsep(3),  strspn(3),  strstr(3), strtok(3),
       strxfrm(3)

COLOPHON

       This page is part of release 3.25 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

								    2010-02-25								 STRING(3)

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

And operator

Discussion started by: rcarnesiii

2. HP-UX

Or operator with if

Discussion started by: babom

3. Programming

ambiguity in program output

Discussion started by: bishweshwar

4. AIX

Fs space ambiguity

Discussion started by: ram1729