Question

C++

Write a function named "FriendsWithPets" that takes a const reference to a std::map of my friends names (std::string) to the number of pets they own (int) and returns the number of friends (int) that have at least one pet.

You should be using the STL algorithms to achieve this, credit is only given if your solution doesn't have any looping constructs (no "while" or "for" keywords anywhere in the solution).

Answer 1

The function is as follows:

// definition of the function.

void FriendsWithPets(map<string,int>data){

// Declare the class type variable.

Test< string, int > val(0);

// Calculate the count.

size_t count = count_if( data.begin(), data.end(), val );

//display the result on console.

cout<<data.size() - count <<endl;

}

The complete program is as follows:

Program screenshots:

Sample Output:

Code to Copy:

// Include the necessary header files.

#include <bits/stdc++.h>

using namespace std;

// Declare template.

template< class E1, class E2 >

// Declare class.

class Test

{

// Declare public members.

public:

Test( const E2& val ) : Tval( val ) {};

bool operator()( const typename std::pair< const E1, E2 >& temp )

{

return (temp.second == Tval);

}

// Declare private members.

private:

const E2 Tval;

};

// definition of the function.

void FriendsWithPets(map<string,int>data){

// Declare the class type variable.

Test< string, int > val(0);

// Calculate the count.

size_t count = count_if( data.begin(), data.end(), val );

//display the result on console.

cout<<data.size() - count <<endl;

}

// Start the main function.

int main(){

// Declare a map

map<string,int>data;

// Add values to the map

data["1"]=0;

data["2"]=1;

data["3"]=1;

data["4"]=3;

data["5"]=5;

data["6"]=0;

data["7"]=2;

data["8"]=0;

// Call the function.

FriendsWithPets(data);

}