I have to two errors in my C++ code on Visual Studio. LNK1120 and LNK2019. I have tried everything to fix the error.(student)

Question

I have tried everything to fix the error like changing properties and other things. the two have are here in this picture. Also here is my code aswell.[NK1120 and LNK2019] I believe we declare the function with what values it takes. Then when we call it we pass variables and lastly when it runs it names those variables. This is my understanding so please help me.(https://i.stack.imgur.com/K5Agg.png)

/******************************************************************************
Basic Template for our C++ Programs.
STRING
*******************************************************************************/
#include <stdio.h>      /* printf, scanf, puts, NULL */
#include <stdlib.h>     /* srand, rand */
#include <time.h>       /* time */
#include <string>       // String managment funtions.
#include <iostream>     // For input and output
#include <cmath>        // For math functions.
#include <math.h>
#include <cstdlib>
using namespace std;
////////////////////////////////////////////////////////////////////////
int main()
{
    int getNumAccidents(string);
    double determineAverage(int,int ,int ,int ,int);
    string findLowest(int, int, int, int, int);

    int north, south, east, west, central;


    north = getNumAccidents("north");
    south = getNumAccidents("south");
    east = getNumAccidents("east");
    west = getNumAccidents("west");
    central = getNumAccidents("central");

    return 0;
}

int getNumberAccidents(string compass)

{
    int accidents;

    cout << "How many accidents are in the " << compass << " region " << endl;
    cin >> accidents;

    return accidents;
}
double determineAverage(int north, int south, int east, int west, int central)
{
    double avg = (north + south + east + west + central) / 5;
    return avg;
}
string findlowest(int north, int south, int east, int west, int central)
{
    int lowest;
    string lowestregion;
    if (north < south &&
        north < east &&
        north < west &&
        north < central)
    {
        lowest = north;
        lowestregion = "north";
    }
    else if (south < north &&
        south < east &&
        south < west &&
        south < central)
    {
        lowest = south;
        cout << "south ";
    }
    else if (west < north &&
        west < east &&
        west < south &&
        west < central)
    {
        lowest = west;
        cout << "west ";
    }
    else if (east < north &&
    east < south &&
    east < west &&
    east < central)
    {
    lowest = east;
    cout << "east ";
    }
    else
    {
        lowest = central;
        cout << "central ";
    }
    cout << "region that had " << lowest << " reported traffic accidents.\n\n";
    return lowestregion;
}

I have tried everything to fix the error like changing properties and other things.