Download Problem Solving Techniques - Lecture Slides | CPE 112 and more Study notes Engineering in PDF only on Docsity!
Electrical and Computer Engineering
1
UAH CPE 112
Problem-Solving Techniques
- Ask questions.
- Look for things that are familiar.
- Solve by analogy.
- Identify the inputs and outputs.
- Divide and conquer.
- Use building blocks (new or existing).
- Merge solutions.
Electrical and Computer Engineering
2
UAH CPE 112
Problem-Solving Case Study
- Problem: A small company needs an interactive program
to figure its weekly payroll. The input data and each
employee’s wages should be saved in a secondary storage
file, and the total wages for the week should be displayed
on the screen so that the payroll clerk can transfer the
appropriate amount into the payroll account.
- Data consists of id, hourly pay rate, and hours worked
- Regular wage for 40 hours, time and a half after that
- Store results in a file called payFile
- Use id 0 to indicate end of data since it is not a valid id
Electrical and Computer Engineering
3
UAH CPE 112
- Four obvious steps
- Get the data
- Compute the results
- Output data
- Output total payroll
Case Study (continued)
Payroll
Get data Compute
results
Output
data
Output total
payroll
Electrical and Computer Engineering
4
UAH CPE 112
Main Algorithm
Open file payFile, Set total payroll to zero
Get Data
As long as the employee number is not zero
Compute Result
Add employee’s wages to the total payroll
Output data
Get data
Output total payroll
Electrical and Computer Engineering
5
UAH CPE 112
Get Data
Prompt user for id number
Read id number
Prompt user for pay rate
Read pay rate
Prompt user for number hours worked
Read number hours worked
Electrical and Computer Engineering
6
UAH CPE 112
Compute Results
If hours worked is greater than 40, then
Wages = 40 * pay rate + (hours – 40) * 1.5 * pay
rate
Otherwise
Wages = hours * pay rate
Electrical and Computer Engineering
7
UAH CPE 112
Output Data
Write id number into payFile
Write pay rate into payFile
Write hours worked into payFile
Write wages into payFile
Electrical and Computer Engineering
8
UAH CPE 112
Output Total Payroll
- Write total payroll to the screen
Electrical and Computer Engineering
9
UAH CPE 112
Payroll Program
// Payroll program // This program computes each employee’s wages and the // total company payroll //**********************************************
#include #include
using namespace std;
void CalcPay (float, float, float&);
const float MAX_HOURS = 40.0; // Maximum normal hours const float OVERTIME = 1.5; // Overtime pay factor
Electrical and Computer Engineering
10
UAH CPE 112
Payroll Program (continued)
int main { float payRate; // Employee’s pay rat float hours; // Hours worked float wages; // Wages earned float total; // Total company payroll int empNum; // Employee ID number ofstream payFile; // Company payroll file
payFile.open(“payfile.dat”); // Open the output file total = 0.0; // Initialize total
Electrical and Computer Engineering
11
UAH CPE 112
Payroll Program (continued)
cout << “Enter employee number: ”; // Prompt cin >> empNum; // Read employee id no. while (empNum != 0) // While employee { // number isn’t zero cout << “Enter pay rate: ”; // Prompt cin >> payRate; // Read hourly pay rate cout << “Enter Hours worked: ”; // Prompt cin >> hours; // Read hours worked CalcPay(payRate, hours, wages); // Compute wages total = total + wages; // Add wages to total payFile << empNum << payRage // Put results in file << hours << wages; cout << “Enter employee number: ”; //Prompt cin >> empNum; // Read ID number } cout << “Total payroll is ” // Print total payroll << total << endl; // on screen return 0; // Indicate successful } // completion
Electrical and Computer Engineering
12
UAH CPE 112
Payroll Program (continued)
void CalcPay(/* in / float payRate, // Employee’s pay rate / in / float hours, // Hours worked / out */ float& wages) // Wages earned
// CalcPay computes wages from the employee’s pay rate // and the hours worked, taking overtime into account
if (hours > MAX_HOURS; // Is there overtime? wages = (MAX_HOURS * payRate) + // Yes (hours – MAX_HOURS) * payRate * OVERTIME; else wages = hours * payRate; // No }
