Comparing char array[ ] with char *array[ ]?

Question

Sorry if the terminology in the title is incorrect but basically I want to compare a char array with a char * array that contains string literals. Basically I have an array:

char temp[6];
cin.get();
cout << "Enter: ";
cin.getline(temp,6);

And:

char *compare[10] = {".- ", "-... ", "-.-. ", "-.. ", ". ", "..-. "};

How do I go about comparing the string entered by the user into "temp" with the "compare" array elements. Example if user enters: " -... " it compares the string entered with every single element of "compare" and check if it matches? I have tried doing comparisons but it always gives me an error saying " ISO C++ forbids comparison between pointer and integer [-fpermissive]|"

If you're using C++, use `std::string`. What you're using is a C-ism and not considered C++. — tambre, Feb 12 '17 at 17:19
Please get a good book. This will be covered. `std::string temp; std::getline(std::cin, temp); static const std:string compare[] = { /* initialize */ }; bool found = false; for (const auto& s : compare) { if (s == temp) { found == true; break;} }` — Martin Bonner supports Monica, Feb 12 '17 at 17:24
@NeilButterworth: It *is*, but using char arrays is making life hard for the OP — Martin Bonner supports Monica, Feb 12 '17 at 17:25
@NeilButterworth I wasn't saying it wasn't valid. Except it smells of someone coming from C. Basically they need a modern C++ book. — tambre, Feb 12 '17 at 17:25

score 1 · Answer 1 · edited May 23 '17 at 12:01

You should use the facilities of the STL wherever applicable always. So that you can change this hullabaloo:

char temp[6];
cin.get();
cout << "Enter: ";
cin.getline(temp,6);

char *compare[10] = {".- ", "-... ", "-.-. ", "-.. ", ". ", "..-. "};

to:

std::string temp;
std::cout << "Enter: ";
std::getline(std::cin, temp);

std::vector<std::string> compare = {".- ", "-... ", "-.-. ", "-.. ", ". ", "..-. "};

Now to find whether the entered string matches:

auto iter = std::find(compare.begin(), compare.end(), temp);
if(iter != compare.end(){
     // You have a match!
}

A full example:

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

int main(){

    std::string temp;
    std::cout << "Enter: ";
    std::getline(std::cin, temp);

    std::vector<std::string> compare = {".- ", "-... ", "-.-. ", "-.. ", ". ", "..-. "};

    auto iter = std::find(compare.begin(), compare.end(), temp);
    if(iter != compare.end(){
         //To obtain index from an iterator
         auto index = std::distance(iter, compare.end());

         std::cout << "We found a match at: " << index << '\n';
    }

}

If you have lots of questions about the code above, you probably want to check The Definitive C++ Book Guide and List

`const auto iter` ? – Martin Bonner supports Monica Feb 12 '17 at 17:26 — Martin Bonner supports Monica, Feb 12 '17 at 17:26

Shravan40 · Answer 2 · 2017-02-12T21:23:15.217

You should use STL feature as much as possible. In your current scenario try using std::string instead of char* and std::vector instead of char* arr.

You can replace your existing code

char temp[6];
cin.get();
cout << "Enter: ";
cin.getline(temp,6);

char *compare[10] = {".- ", "-... ", "-.-. ", "-.. ", ". ", "..-. "};

By this

std::string temp;
std::cout << "Enter: ";
std::getline(std::cin, temp);

std::vector<std::string> compare = {".- ", "-... ", "-.-. ", "-.. ", ". ", "..-. "};

Now you can iterator over this compare vector like

for(const auto& iter : compare) {
    // Do the comparison to check whether it's a match or not.
}

The name of your loop variable in the for loop is *very* misleading. It is *not* an iterator, it is an element of the array. — Martin Bonner supports Monica, Feb 12 '17 at 21:22

Comparing char array[ ] with char *array[ ]?

2 Answers2