Word comparison - Vectors /Getopt

Please Help!!!

My understanding of getopt is very limited.
I do however realise that argv[0] is the exe file, argv[1] is the option, argv[2] is the word to compare and argv[3] is the dictionary or document I want to search(file .txt).
I'm trying to set a pointer to the dictionary and then iterate through it to see if there is a match with the argv[2] (input word) to the text file, and if there is a match out put the argv[2] word.
Below is my current code that has errors
main.cpp:61: error: no match for 'operator==' in 'list == *(argv + 12u)'
main.cpp:64: error: no match for 'operator*' in '*list'
Any help would be greatly appreciated.

Code:

#include <cstdlib>
#include <unistd.h>
#include <vector>
#include <iostream>
#include <string>
#include <iterator>


using namespace std;


int main(int argc, char** argv) {


    enum {
        WHOLE, PREFIX, SUFFIX, ANYWHERE, EMBEDDED
    } mode = WHOLE;
    bool jumble = false;
    bool ignore_case = false;
    bool invert = false;
    string length = "0,0";
    int c;
    string input;
    vector <string> list;
    vector <string>::iterator i;


    while ((c = getopt(argc, argv, ":wpsaejivn:")) != -1) {
        switch (c) {
            case 'w': mode = WHOLE;
                break;
            case 'p': mode = PREFIX;
                break;
            case 's': mode = SUFFIX;
                break;
            case 'a': mode = ANYWHERE;
                break;
            case 'e': mode = EMBEDDED;
                break;
            case 'j': jumble = true;
                break;
            case 'i': ignore_case = true;
                break;
            case 'v': invert = true;
                break;
            case 'n': length = optarg;
                break;
            default: WHOLE;
                break;
        }
    }
    argc -= optind;
    argv += optind;


    switch (mode) {
        case WHOLE:
            while(argc != -1){
                list == argv[3];
                for(i == list.begin(); i != list.end(); i++)
                if(argv[1] == argv[3]){
                    cout << *list << endl;
                }else cout << "Did not work again" << endl;
            }           
                
    }
    return 0;
}

> list == argv[3];
You need to
- open the filename (in argv[3])
- read each line, and store each line in your 'list' vector
- close the file

> if(argv[1] == argv[3])
These are two pointers to 'C' style strings.
You need to use strcmp() to compare these.


> cout << *list << endl;
You need to output the iterator, not the list