Question

Write a int function that accepts as parameter the name of a candidate and return the number of votes received by the candidate. So, if the user enters Duck, the output will be 6000. Of course, if the given name does not exist, display an appropriate message.

Need help with the above here is what i have so far:

#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <map>

using namespace std;

// Get the details from the user for the candidates
void askdetails(vector<string>& name, vector<int>& vote)
// The vector is passed by reference
{
   string s;
   int v;
   while (true)
   {
       cout << "Give name of contestant (press # and enter to exit)";
       cin >> s;
       if (s == "#") break;
       name.push_back(s);
       cout << "Enter no of votes for " << s << endl;
       cin >> v;
       vote.push_back(v);
   }
}

// Get the winner of the vote and return name
string winner(const vector<string>& name, const vector<int>& vote)
{
   string s;
   int i, in = 0, m = 0;
   for (i = 0; i < vote.size(); i++)
       if (vote[i] > m)
       {
           m = vote[i];
           in = i;
       }
   cout << "\nThe winner of the election is " << name[in] << " with " << vote[
       in] << " votes" << endl;
   return name[in];
}

// Get the loser of the vote and return name
string loser(const vector<string>& name, const vector<int>& vote)
{
   string s;
   int i, in = 0, m = INT_MAX;
   for (i = 0; i < vote.size(); i++)
       if (vote[i] < m)
       {
           m = vote[i];
           in = i;
       }
   cout << "The loser of the election is " << name[in] << " with " << vote[in]
       << " votes" << endl;
   return name[in];
}

//Calculate the average number of votes
int averagevotes(const vector<int>& vote)
{
   int i, s = 0;
   for (i = 0; i < vote.size(); i++)
       s += vote[i];
   cout << "\nAverage votes\t" << s / vote.size() << endl;
   return s / vote.size();
}

// Claculate the total number of votes
int totalvotes(const vector<int>& vote)
{
   int i, s = 0;
   for (i = 0; i < vote.size(); i++)
       s += vote[i];

   cout << "\nTotal\t\t" << s << endl;
   return s;
}

// Sort the out put by number of votes
void sortname(const vector<string>& name, const vector<int>& vote,
map<string, int>& m) // The vector is passed by reference
{
   int i;
   for (i = 0; i < vote.size(); i++)
       m[name[i]] = vote[i];
}

void display(map<string, int> m, const vector<int> vote)
{
   // Output the summary header
   cout << "\nCandidate" << "\t" << "Votes Recieved" << "\t" <<
       "% of Total votes" << endl;

   map<string, int>::iterator it;
   int i, s = 0;
   for (i = 0; i < vote.size(); i++)
       s += vote[i];
   for (it = m.begin(); it != m.end(); ++it)
   {
       // output vote details in the table
       cout << endl;
       cout << it->first << "\t\t" << it->second << "\t\t";
       printf("%.2f", ((float)it->second / (float)s) * 100);
       cout << endl;
   }
}

int main()
{
   // delcare variables
   vector<int> vote;
   vector<string> name;
   map<string, int> m;

   // get the user input
   askdetails(name, vote);

   //sort and display the candidate information
   sortname(name, vote, m);
   display(m, vote);

   // calculate the total votes and the average votes
   totalvotes(vote);
   averagevotes(vote);

   // output the winner and loser details
   winner(name, vote);
   loser(name, vote);

   return 0;
}

Answer 1

So far you've made a map of the candidate names and their corresponding votes. We'll use this same map to search for the candidate name and query the no. of votes from this map only.

First, we define the function that counts the votes:

//START FUNCTION 1
int count_votes(string name,map<string, int> m){ //Pass the name of candidate and the map
if ( m.find(name) == m.end() ) { //means the name is not found

return -1; // returning -1 to indicate error
} else {
return m.at(name); // return value at the key "name"
}
}

//END FUNCTION 1

Second, we define the function that acts as an interface with the user:

//START FUNCTION 2
void display_count(map<string,int>m){ //display the vote count of desired candidates, takes in the map of name and votes
string name; //This string is used to query the map.
while(true){
cout<<"Enter the name of candidate (Enter # and enter to exit):";
cin>>name; //Taking user input for the desired candidate
if(name=="#") //If user inputs #
break; //break loop and return

//find the no. of votes of "name" from the map "m" by invoking the count_votes function
int votes = count_votes(name,m);
if (votes == -1)
cout<<"Error: Candidate does not exist!"<<endl; //print error message in case Candidate not found
else
cout<<"No. of votes of "<<name<<" is: "<<votes<<"."<<endl; //print no. of votes
}

return 0;
}

//END FUNCTION 2

Third, we call the display_count funtion in our main function:

display_count(m); //operate on map "m"