C++ :: Search Function For Speaker Bureau Program

I'm working on this program for homework an here is the problem:

Write a program that keeps track of a speakers bureau. The program should use a structure to store the following data about a speaker.

Name
Telephone Number
Speaking Topic
Fee required

The program should use an array of at least 10 structures.It should let the user enter data into the array, change the contents of any element, and display all the data stored in the array. The program should have a menu-driven user interface.

So I did the program which is below but now it is asking this:

Add a function that allows the user to search for a speaker on a particular topic. It should accept a key word as an argument and then search the array for a structure with that key word in the searching topic field. All structures that match should be displayed. If no structure matches, a message saying so should be displayed.

Now this where I get stuck, I'm having trouble figuring out how to write down the search function in this program. A function that can work and how to get it to match the topics listed by each speaker.

#include <iostream>
#include <string>
#include <iomanip>
using namespace std;
struct speakerBureau {

[Code] .....