i have a problem with this class.
the goal is to make the main function work properly. we were supposed to implement the "And" function object so that the code will work. i can't find what is the problem with our solution.
(the solution start and end are marked in comments in the code before the "main" function)
can you please help?
thanks
#include <iostream>
#include <algorithm>
using namespace std;
class NotNull
{
public:
bool operator()(const char* str) {return str != NULL;}
};
class BeginsWith
{
char c;
public:
BeginsWith(char c) : c(c) {}
bool operator()(const char* str) {return str[0] == c;}
};
class DividesBy {
int mod;
public:
DividesBy(int mod) : mod(mod) {}
bool operator()(int n) {return n%mod == 0;}
};
//***** This is where my sulotion starts ******
template <typename Function1, typename Function2, typename T>
class AndFunction
{
Function1 f1;
Function2 f2;
public:
AndFunction(Function1 g1, Function2 g2) : f1(g1), f2(g2) {}
bool operator()(T t)
{
return (f1(t) && f2(t));
}
};
template <typename Function1, typename Function2, typename T>
AndFunction <Function1, Function2, T>
bool And(Function1 f1, Function2 f2)
{
return AndFunction<Function1, Function2, T>(f1, f2);
}
//***** This is where my sulotion ends ******
int main(int argc, char** argv)
{
int array[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
char* strings[4] = {"aba", NULL, "air", "boom"};
cout << count_if(array,array+10,And(DividesBy(2),DividesBy(4))) << endl;
// prints 2, since 4 and 8 are the only numbers which can be divided by
// both 2 and 4.
cout << count_if(strings,strings+4,And(NotNull(),BeginsWith('a'))) <<endl;
// prints 2, since only "aba" and "air" are both not NULL and begin
// with the character 'a'.
return 0;
}