Question re: iterators...ASAP...please...

Do I need to use iterators when comparing strings within vectors?
I need to compare strings from one vector to strings in another vector.  The size of the vectors are different.
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pankajtiwaryConnect With a Mentor Commented:
Hi jewee,

Do not confuse. Iterators are objects to iterate through the elements of a container ( e.g vector ), if you want to iterate through a vector and so *something* you need iterators. Do check this example out.

// Code not tested
#include <iostream>

using namespace std ;

int main() {
    vector v1<string>(2);
    vector v2<string>(4);



    for ( vector<string>::const_iterator it1 = v1.begin(); it1 != v1.end(); it1++) {
        for ( vector<string>::const_iterator it2 = v2.begin(); it2 != v2.end(); it2++) {
            if ( *it1 == *it2 )
    return 0 ;

Hope this helps.

jkrConnect With a Mentor Commented:
Ooops, haven't seen that you opened a seperate Q - here's the code again I posted in the last one:

string str = "substring";
vector<string> vs;

for ( vector<string>::iterator i = vs.begin(); i != vs.end(); ++i) {

    if ( -1 != i->find(str)) {

        cout << "Found " << str->c_str() " in in " i->c_str() << endl;

If you want to find the exact match, use

if ( *i == str )

like pankajtiwary already suggested.
gugarioConnect With a Mentor Commented:
There's two ways you can access elements in a vector... one is using the bracket operator, so if you have...

vector<string> a;
vector<string> b;

you could do

if (a[0] == b[1]) cout << "equal";

another is dereferencing an iterator.. so you could have iteractors to the vectors, like

vector<string>::iterator t1 = a.begin();
vector<string>::iterator t2 = b.begin();

if (*t1 == *t2) cout << "equal";

bracket operators, in my opinion, are easier to use.  and part of the reason you would use a vector is so that you could do the direct access with the brackets..

iterators are good i guess if you need to iterate through both vectors completely... but you could still do it with for loops.

hope that helps.

if you like to use bracket operators like Gustavo, vect.size() is the upper bound.
rstaveleyConnect With a Mentor Commented:
There are a lot of nice algorithms you can use that do the iterator work for you.

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

typedef std::vector<std::string> StringVector;

class match {
      const std::string &name;
      const StringVector& cmp;
      match(const StringVector& cmp,const std::string& name) : cmp(cmp),name(name) {}
      void operator()(const std::string& str) const
            bool found = find(cmp.begin(),cmp.end(),str) != cmp.end();
            std::cout << str << (found?" found ":" not found ") << "in " << name << '\n';

int main()

      StringVector v1;

      StringVector v2;

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