CODEWITHSUNDEEP
c++
user7
user7

Reputation: 133

Intersection and union of two strings

I have to eliminates any occurrence of string 2 in string 1 and also find the intersection of two strings.

Here is what I have tried:

#include "stdafx.h"
#include "stdio.h"
#include "conio.h"
#include "string.h"

class operation
{
public:
    char string1[100];
    char string2[50];


    operation(){};
    operation(char a[100], char b[50]);
    operation operator+(operation);
    operation operator-(operation);
    operation operator*(operation);
};

operation::operation(char a[100], char b[50])
{
    strcpy(string1, a);
    strcpy(string2, b);
}

operation operation::operator +(operation param)
{
    operation temp;
    strcpy(param.string1, temp.string1);
    strcpy(param.string2, temp.string2);
    strcat(temp.string1, temp.string2);
    return (temp);
}

operation operation::operator -(operation param)
{
    operation temp;
    strcpy(param.string1, temp.string1);
    strcpy(param.string2, temp.string2) ;
    for (int i = 0; i<strlen(temp.string2); i++)
    {
        temp.string1.erase(i, 1);
    }
    return (temp);
}

operation operation::operator *(operation param)
{
    operation temp;
    strcpy(param.string1, temp.string1);
    strcpy(param.string2, temp.string2);
    char result[50];
    for(int i = 0; i<strlen(temp.string2); i++)
    {
        if( temp.string1.find( temp.string2[i] ) != string::npos )
            result = result + temp.string2[i];
    }

    return (temp);

}

I am getting compiler errors and also I am not sure what I am trying is correct or not.

The errors are as follows:

C2228: left of .erase must have class/struct/union
C2228: left of .find must have class/struct/union

Upvotes: 5

Views: 12516

Answers (3)

johnsyweb
johnsyweb

Reputation: 141928

Happily, in C++ set difference, intersection, and union algorithms have already been implemented in the standard library. These can be applied to strings like any container class.

Here is a demonstration (you could do this with simple char arrays, but I'm using std::string for clarity):

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

int main()
{
    std::string string1 = "kanu";
    std::string string2 = "charu";
    std::string string_difference, string_intersection, string_union;

    std::sort(string1.begin(), string1.end());
    std::sort(string2.begin(), string2.end());

    std::set_difference(string1.begin(), string1.end(), string2.begin(), string2.end(), std::back_inserter(string_difference));
    std::cout << "In string1 but not string2: " << string_difference << std::endl;

    std::set_intersection(string1.begin(), string1.end(), string2.begin(), string2.end(), std::back_inserter(string_intersection));
    std::cout << "string1 intersect string2: " << string_intersection << std::endl;

    std::set_union(string1.begin(), string1.end(), string2.begin(), string2.end(), std::back_inserter(string_union));
    std::cout << "string1 union string2: " << string_union << std::endl;
}

Run it!

How you implement this in your operation class is left as an exercise.

Upvotes: 9

K-ballo
K-ballo

Reputation: 81389

If strcpy( string1... compiles then string1 is a char* and not a std::string. You seem to be mixing C and C++ functionality for strings. Choose one and stick with it (I'd say std::string since you are doing C++)

Upvotes: 1

paulsm4
paulsm4

Reputation: 121829

  1. This is C++ (not C: C doesn't have operator overloading)

  2. You need to show us your class definition before we can help identify the compile error.

  3. If you don't have a class definition for "operator", that alone explains the error :)

  4. If you're using C++, you should probably be using standard C++ "string" (instead of C "char []" arrays). Using "string" will also affect your implementation code.

  5. Q: This wouldn't be a homework assignment, would it? If so, please add "homework" to your tags.

Thanx in advance .. PSM

Upvotes: 0

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