CODEWITHSUNDEEP
c++stringvector
Daniel Rad
Daniel Rad

Reputation: 38

c++ search for string in an vector of strings

I am working on a project to read a Context-free Grammar and represent it 1.Vectorial, 2. Branched chained lists, 3. Array (Table). I encounter a problem with string comparison. When I read a string from keyboard representing right side of a Production rule, I want to check if that string exists in a vector of strings. The problem is that comparison is not working right. If the string I compare is the first string from the vector of strings than the comparison is working fine. But if the string I compare is a string from the vector of strings other than first comparison is not working, it's like the string is not from the vector of strings. Sorry for my English. I better let the code explain

bool is(string &s, vector<string> &v) {
    for (auto i : v) {
        return (i.compare(s)==0) ? true : false;
    }
}

This function returns true only if s=v[0], otherwise returns false even if s=v[2]

Upvotes: 0

Views: 624

Answers (1)

Radioactive Epic Face
Radioactive Epic Face

Reputation: 105

To do that you'd have to loop into the vector with a for loop and compare every string in it, it would be something like:

#include <iostream>
#include <string>
#include <vector>

using namespace std;

bool doExists(string s, vector<string> v) {
    for (int i=0;i<v.size();i++) {
        if (s.compare(v[i]) == 0) {
            return true;
        }
    }
    return false;
}

int main(){
    vector<string> phrases = {"Hello!", "I like potatos!","I like fries.","How are you today?","I'm good.","Hello!"};
    int helloLocated = doExists("Hello!", phrases);
    cout << helloLocated;
}

The console would print 1.

Upvotes: 1

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