error: invalid conversion from 'char' to 'const char*'

[holyheck]

Hey guys, so I want to make a program that finds and shows me all the words that contain a given amount of letters and a given letter in a specific position in a word, for example:

say I have the words: egg, desk, cart, tart, mouse, house
all those words are in a text file

the first variable I introduce is going to be the number of letters I want my program to show in the console.

so if I say 4, it's going to give me: desk, cart and tart

afterwards, its going to ask me for a letter, let's say the letter a.
then, its going to ask me for a position(a number which represents the place of a letter in a word), let's say 2;

so then it should give me these two words: cart and tart

the first part works fine but then when I try and make it so it filters out the words with non corresponding letters in a position I have the error: invalid conversion from 'char' to 'const char*'

here's the code:

#include <iostream>
#include <string.h>
#include <math.h>
#include <fstream>
#include <string>
using namespace std;

ifstream f("words.txt");

struct wordData {
    char word[20];
}data[100];

int main()
{
    int nr_char;        //this variable holds the number of letters the words that you want to search for have
    char lit[1];              //a letter
    int pos;                //the position of said letter in a word
    int n;                    //number of words in the text file
    f >> n;                    //the first thing in the text file is the number of words
    for(int i=1; i<=n; i++)
    {
        f >> data[i].word;
        cout << data[i].word << " ";             //this shows all the words from the text file in the console
        cout << endl;
    }

    do
    {
        cout << endl;
        cout << "Number of characters: ";
        cin >> nr_char;
        cout << endl;

        cout << "Words with " << nr_char <<" letters: "<<endl<<endl;
        for(int i=1; i<=n; i++)
        {
            if(nr_char == strlen(data[i].word))
                cout << data[i].word << endl;                  //it works well up until this point, so far it has shows all the words with the number of letters you introduced

            cout<<"enter a letter:";
            cin>>lit;
            cout<<endl;
            cout<<"The position of the letter in a word:";
            cin>>pos;
            cout<<"All words with the given data: "<<endl;

         if(strcmp(data[i].word[pos], lit))  //error: invalid conversion from 'char' to 'const char*' [-fpermissive]
                cout<<data[i].word<<endl;
        }

    }while(nr_char != 0);


    return 0;
}

[Repeater]

if(strcmp(data[i].word[pos], lit)) //
Let's look at the reference page for the function strcmp; http://www.cplusplus.com/reference/cstring/strcmp/

So it takes two parameters, and they both need to be char-pointers.

What's data[i].word[pos]?

data is an array of wordData objects, so data[i] is a wordData object, so data[i].word is a char array, so data[i].word[pos] is a char.

Is a char the same thing as a char-pointer? No, it is not. The function strcmp takes char-pointers. You're trying to give it a char. When you call a function, you have to give it the right kind of parameters. You have to give strcmp two char-pointers.


As an aside, you're doing this all wrong. Don't use arrays. Use a vector. Don't use a char array. Use a string, You're writing a horrible mix of C and C++ code and it's making everything much harder for you.

[Ganado]

char lit[1];
Why even have an array if you know it's 1 letter long...?

Also, avoid global variables (f, data[100]).