Function for checking if one array is a subset of another

[broski83]

My goal is to find out whether one array is a subset of another, in the same order but not necessarily consecutively. For example:
string major[10] = { "a", "b", "c", "f", "b"}
string major[10] = { "b", "f"}
Would return true but if the second array was
{"c", "a"} would return false.

bool subsequence(const string a1[], int n1, const string a2[], int n2)
{
	for (int i = 0; i < n1; i++)
	{
		for (int j = 0; j < n2; j++) 
		if (a1[j] == a2[i])   //i want to cycle through a1[] to see if a component matches a component of a2 
                                  
		{
			if ((j == n2-1) && (a1[i] == a2[j]))
			{
				return true;
			}
		}
		
		else
		{
			return false;
		}
		
	}
	
}

[prestokeys]

Generalized to allow any container holding any type:

#include <iostream>
#include <algorithm>
#include <string>

template <class ForwardIterator1, class ForwardIterator2>
bool subsequence (ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2, ForwardIterator2 last2) {
	while (first2 != last2)
	{
		ForwardIterator1 it = std::find (first1, last1, *first2);
		if (it == last1)	
			return false;
		++first2;  first1 = it; 
	}
	return true;	
}


int main() {
	std::string A[] = {"a", "b", "c", "f", "b"};
	std::string B[] = {"b", "f"};
	std::string C[] = {"c", "a"};
	if (subsequence (A, A+5, B, B+2))
		std::cout << "B is a subsequence of A." << std::endl;
	else
		std::cout << "B is not a subsequence of A." << std::endl;
	if (subsequence (A, A+5, C, C+2))
		std::cout << "C is a subsequence of A." << std::endl;
	else
		std::cout << "C is not a subsequence of A." << std::endl;
	std::cin.get();
}

Output:

B is a subsequence of A.
C is not a subsequence of A.

[broski83]

Cannot use algorithm library, must write the function from scratch.

[prestokeys]

Use myFind instead of std::find then:

template<class InputIterator, class T>
InputIterator myFind (InputIterator first, InputIterator last, const T& val)
{
  while (first != last) 
  {
    if (*first == val) 
       return first;
    ++first;
  }
  return last;
} 

Now replace
ForwardIterator1 it = std::find (first1, last1, *first2);
with

ForwardIterator1 it = myFind (first1, last1, *first2);