Question
The following code uses two arrays, one to store products and another to store roduct IDs (a better organization would be to use a single array of a class or struct, but that is not the subject of this Programming Project). The function getProductID takes as input the two arrays, the length of the arrays, and a target product to search for. It then loops through the product name array; if a match is found, it returns the corresponding product ID:
int getProductID( int ids[], string names[], int numProducts, string target)
{
for ( int i=0; i < numProducts; i++)
{
if (names[i] == target)
return ids[i];
}
return -1; // Not found
}
int main() // Sample code to test the getProductID function
{
int productIds[] = {4, 5, 8, 10, 13};
string products[] = {"computer","flash drive",
"mouse","printer","camera"};
cout << getProductID(productIds, products, 5, "mouse") << endl;
cout << getProductID(productIds, products, 5, "camera") << endl;
cout << getProductID(productIds, products, 5, "laptop") << endl;
return 0;
}
One problem with the implementation of the getProductID function is that it returns the special error code of -1 if the target name is not found. The caller might ignore the -1, or later we might actually want to have -1 as a valid product ID number. Rewrite the program so that it throws an appropriate exception when a product is not found instead of returning -1.
Answer
Complete Program:
// Header files section
#include <iostream>
#include <string>
using std::string;
using std::cout;
using std::endl;
// getProductID function implementation
int getProductID(int ids[], string names[], int numProducts, string target)
{
for (int i = 0; i < numProducts; i++)
{
if (names[i] == target)
return ids[i];
}
// throw an error message
throw (target + " is not found.");
} // end of getProductID function
// start main function
int main()
{
int productIds[] = { 4, 5, 8, 10, 13 };
string products[] = { "computer", "flash drive", "mouse", "printer", "camera" };
// use try/catch to handle the exceptions
try
{
cout << getProductID(productIds, products, 5, "mouse") << endl;
cout << getProductID(productIds, products, 5, "camera") << endl;
cout << getProductID(productIds, products, 5, "laptop") << endl;
}
catch (string message)
{
// print the error message
cout << "Error: " << message << endl;
}
return 0;
} // end of main function
Sample Output:
