Finding Index in string C++

Question

#include<iostream>
#include<vector>
#include<string>
using namespace std;

int contain(vector<string> &s_vector, string check)
    {
    cout<<"Input a string to check: ";
    cin>>check;
    if(s_vector=check) 
     return find(&s_vector);
    else
    return -1;
    }

int main(){
    vector<string>s_vector;

    cout<<"Input the size of string vector: ";
    int size;
    cin>>size;

    cout<<"Input "<<size<<"strings: \n"; 
    cin>>s_vector[size];

    cout<<"Strings in the string vector: ";
    for(int i=0; i<s_vector.size(); i++)
    cout<<s_vector[i]<<" ";

    contain(s_vector, string check);

    return 0;
} 

I'm trying to make a code where you can find the index of a string. For example the output would be like:

Input the size of string vector: 3
Input 3 strings:
asd
lkj
qere
Input a string to check: lkj
1

But there seems to be some errors in the int contain~section, and if I take out the int contain~ section and run the program, it keeps saying "the run has stopped"whenever I try to input the strings. I'm new to C++ so I could really use your help thanks.

Answer 1

What your contain function might look like:

int contain(const vector<string>& s_vector)
{
    cout << "Input a string to check: ";
    string check;
    cin >> check;
    for (int i = 0; i < s_vector.size(); i++)
        if (s_vector[i] == check)
            return i;

    return -1;
}

There's no need to pass the local variable check to the function. We're comparing the strings inside the vector one by one by using operator []. main would look something like this:

int main()
{
    vector<string>s_vector;

    cout<<"Input the size of string vector: ";
    int size;
    cin>>size;

    cout << "Input " << size << "strings: \n"; 
    for (int i = 0; i < size; i++)
    {
        string str;
        cin >> str;
        s_vector.push_back(str);
    }

    cout<<"Strings in the string vector: ";
    for(int i=0; i<s_vector.size(); i++)
    cout<<s_vector[i]<<" ";

    int i = contain(s_vector);
    cout << "Index: " << i;

    return 0;

}