CODEWITHSUNDEEP
c++arraysstringstrcmp
bahadirtr
bahadirtr

Reputation: 53

Working with strcmp and string array

I'm trying to eliminate extra elements in the string array and I wrote the code below. There seems a problem with strcmp function and string arrays. Strcmp doesn't accept the string array elements that way. Can you help me fix that? array3 is string array. I'm coding in C++ and What I want to do is like there are multiple "apple"s or "banana"s in the string array. But I only need one "apple" or one "banana".

for(int l = 0; l<9999; l++)
{
    for(int m=l+1;m<10000;m++)
        if(!strcmp(array3[l],array3[m]))
        {
            array3[m]=array3[m+1];
        }
}

Upvotes: 0

Views: 4023

Answers (3)

Diaa
Diaa

Reputation: 879

strcmp works on Cstrings only so if you wanna use it I suggest you alter it to the following: strcmp(array3[l].c_str(),array3[m].c_str()) which makes the strings C Strings.

Another option would be to simply compare them with the equality operator array3[l]==array3[m] this would tell you if the strings are equal or not.

Another way to do what you're trying to do is just to put the array in a set and iterate over it. Sets don't take more than one string of the same content!

References:

Upvotes: 0

SingerOfTheFall
SingerOfTheFall

Reputation: 29966

First of all, you can use operator== to compare strings of std::string type:

std::string a = "asd";
std::string b = "asd";
if(a == b)
{
//do something
}

Second, you have an error in your code, provided 10000 is the size of the array:

array3[m]=array3[m+1];

In this line you are accessing the m+1st element, with m being up to 10000. This means you will eventually try to access the 10001st element, and get out of array bonds.

Finally, your approach is wrong, and this way will not let you remove all the duplicate strings. A better (but not the best) way to do it is this (pseudocode):

std::string array[];//initial array
std::string result[];//the array without duplicate elements
int resultSize = 0;//The number of unique elements.
bool isUnique = false;//A flag to indicate if the current element is unique.

for( int i = 0; i < array.size; i++ )
{ 
    isUnique = true;//we assume that the element is unique
    for( int j = 0; j < result.size; j++ ) 
    {
        if( array[i] == result[j] )
        {
            /*if the result array already contains such an element, it is, obviously, 
            not unique, and we have no interest in it.*/
            isUnique = false;
            break;
        }
    }
    //Now, if the isUnique flag is true, which means we didn't find a match in the result array,
    //we add the current element into the result array, and increase the count by one. 
    if( isUnique == true )
    {
        result[resultSize] = array[i];
        resultSize++;
    }
}

Upvotes: 1

u25891
u25891

Reputation: 611

strcmp returns 0 on equality, so if (strcmp(s1,s2))... means "if the strings are equal then do this...". Is that what you mean?

Upvotes: 1

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