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c++stringfunctioncountstl
r_ranjan
r_ranjan

Reputation: 199

Is there any function in C++ std::string that count total number of same starting characters of two strings or any best way to do

Eg.

abcfgf
abdef

ans=2 {"ab" is a common starting character}

Upvotes: 3

Views: 630

Answers (2)

gsamaras
gsamaras

Reputation: 73424

It seems that there is a buildin function to do this, as shown in this answer.

However, you could do it by simply using a loop (if you want, but would not suggest it), like this:

#include <iostream>
#include <string>

using namespace std;

int main()
{
    string str1 = "abcfgf";
    string str2 = "abdet";

    int counter = 0;

    for(int i = 0; i < str1.size() && i < str2.size(); ++i)
        if(str1[i] == str2[i])
            counter++;

    cout << counter << endl;
    return 0;
}

Output:

2

Upvotes: 1

Ami Tavory
Ami Tavory

Reputation: 76366

You could use std::mismatch, which returns a pair of iterators indicating the respective iterators where sequences start to differ.

To count the length of common prefixes, for example, you could do the following:

#include <iostream>                                                                                                                                                                                         
#include <iterator>
#include <string>
#include <algorithm>
using namespace std;

int main() {
    const string l = "abcde", r = "abcdfgh";
    cout << distance(begin(l), mismatch(begin(l), end(l), begin(r)).first) << endl;
}

Upvotes: 12

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