In-Class Exercise
Basic Concepts
This exercise covers block scope and references.
Given Information
The following code is extracted from the Example in the Chapter on Modular Programming.
Client Module
main.h
// Modular Example
// main.h
#define NO_TRANSACTIONS 3
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main.cpp
// Modular Example
// main.cpp
#include "main.h"
#include "Transaction.h"
int main() {
int i;
struct Transaction tr;
for (i = 0; i < NO_TRANSACTIONS; i++) {
enter(&tr);
display(&tr);
}
}
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Transaction Module
Transaction.h
// Modular Example
// Transaction.h
struct Transaction {
int acct;
char type;
double amount;
};
void enter(struct Transaction* tr);
void display(const struct Transaction* tr);
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Transaction.cpp
// Modular Example
// Transaction.cpp
#include <iostream>
using namespace std;
#include "Transaction.h"
void enter(struct Transaction* tr) {
cout << "Enter the account number : ";
cin >> tr->acct;
cout << "Enter the account type (d for debit, c for credit) : ";
cin >> tr->type;
cout << "Enter the account amount : ";
cin >> tr->amount;
}
void display(const struct Transaction* tr) {
cout << "Account " << tr->acct;
cout << ((tr->type == 'd') ? " Debit $" : " Credit $") << tr->amount;
cout << endl;
}
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Your Task
Incorporate into the above code the following simplifications:
- limit the use of the struct
keyword wherever possible
- define the sentinel i within the for
block's scope instead of outside its scope
- pass the Transactions by references instead of by address wherever possible
Client Module
In your updated implementation file for the client module fill in the
missing code:
- define an instance of a Transaction
- define the sentinel
- insert the proper argument in each function call
// Basic Concepts
// h1.cpp
#include "h1.h"
#include "Transaction.h"
int main() {
for ( i = 0; i < NO_TRANSACTIONS; i++) {
enter( );
display( );
}
}
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Transaction Module
Transaction.h
In your updated header file for the Transaction module fill in the missing code:
- simplify the parameter list in each function prototype
- pass-by-reference rather than pass-by-address in each prototype
// Basic Concepts
// Transaction.h
struct Transaction {
int acct;
char type;
double amount;
};
void enter( );
void display( );
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Transaction.cpp
In your updated implementation file for the Transaction module
fill in the missing code:
- simplify the parameter list in the function header of each function definition
- pass-by-reference rather than pass-by-address in each function header
- complete the syntax within the body of each function definition
// Basic Concepts
// Transaction.cpp
#include <iostream>
using namespace std;
#include "Transaction.h"
void enter( ) {
cout << "Enter the account number : ";
cin >> ;
cout << "Enter the account type (d for debit, c for credit) : ";
cin >> ;
cout << "Enter the account amount : ";
cin >> ;
}
void display( ) {
cout << "Account " << ;
cout << (( == 'd') ? " Debit $" : " Credit $") << ;
cout << endl;
}
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