Question

c++ program

Notes

1. Your program should use named string constant for the file name to open the file. Do not add any path to the file name because the path on your computer is not likely to exist on the computer the instructor uses to grade the program. Points may be deducted if you don't follow this instruction.

2. Split statements and comments longer than 80 characters into multiple lines and use proper indentations for the split portions.

3. You should not use "break" or "continue" in your code.

4. You should not return from the middle of a function.

5. When you need to cast a variable to a different type, don't use the C-style casting. For example, (char *)ptr will not be accepted.

(Lab2b.cpp) This program has two parts. The first part is to produce a set of nutrition data and save it to a file in binary format. Then the program retrieves a certain nutrition data from the binary file.

The program must be written in accordance to the following plan:

Define Data Structure

Define a data structure named NutritionData that contains these fields

foodName (array of 40 char) , use an all uppercase integer constant identifier for the size.

servingSize (double)

calFromCarb (double)

calFromFat (double)

calFromProtein (double)

totalCalories (double)

Use the data types in parentheses for the fields.

Write necessary function prototypes. You should have at least the following two functions:

- A function that can save an array of NutritionData to a binary file. The function returns true if the binary file has been created and the data has been written to the file. Otherwise it returns false. Choose a meaningful identifier in camelCase for the function. For parameters, see the definition description below.

- A function that can retrieve and return a certain nutrition data record from a binary file. The function returns true if the record has been retrieved; otherwise it returns false. Choose a meaningful identifier in camelCase for the function. For parameters, see the definition description below.

Write the main Function

Define a string constant for the file name. The constant identifier should be all uppercase. The file name shall be called "nutrition.dat". The constant identifier should be used every time the file name is needed in the main function.

Define and initialize an array of NutritionData using the following data:

Apples raw, 110, 50.6, 1.2, 1.0

Bananas, 225, 186, 6.2, 8.2

Bread pita whole wheat, 64, 134, 14, 22.6

Broccoli raw, 91, 21.9, 2.8, 6.3

Carrots raw, 128, 46.6, 2.6, 3.3

Each record of data contains these fields: food name, serving size in grams, calories from carb, calories from fat and calories from protein.

Use a range-based for loop to iterate through the array of NutritionData and update the totalCalories field of each nutrition data.

Call the function that can save the array of NutritionData to "nutrition.dat".

If the call was successful, call the function that can retrieve a nutrition data record to retrieve the third record from "nutrition.dat".

If the call was successful, display the retrieved record. Otherwise, print "The desired structure cannot be extracted."

Write Function Definitions

- For the function that can save an array of NutritionData to a binary file.

The function should have the following parameters:

A parameter for the file name.

A pointer parameter that points to a NutritionData.

A parameter for the number of NutritionData.

Parameters should be in camelCase. The function returns true or false.

If the file already exists, print the message, "The file filename is an existing file. You can either delete the file or move it to another location and then run the program again." Replace the word filename with the value of the file name parameter.

Create a binary file for output using the file name parameter.

Write the array of NutritionData passed in through parameters to the file in binary format.

Close the file.

The function returns true if the file has been opened successfully and all records have been written to the file. Otherwise, it should return false.

- For the function that can retrieve a nutrition data.

The function should have the following parameters:

A parameter for the file name.

A reference parameter for returning the retrieved NutritionData.

A parameter for the desired structure. It must be a positive integer. If the value is 1, the function will attempt to return the first structure on file. If the value is 2, the function will attempt to return the second structure on file. And so on.

Parameters should be in camelCase. The function returns true or false.

Open the file as an input binary file using the file name parameter.

If the file doesn't exist, print the message, "The file filename cannot be opened." Replace the word filename with the value of the file name parameter.

Access the desired record from the file. The program should use the seek mechanism to access the desired record.

Read the desired record and store that in the passed NutritionData parameter.

Close the file.

The function returns true if the file has been opened successfully and the desired record has been retrieved and stored in the parameter. Otherwise, it should return false.

Test The Program

The output should look exactly as follows:

Food Name: Bread pita whole wheat
Serving Size: 64.0 grams
Calories Per Serving: 170.6
Calories From Carb: 134.0
Calories From Fat: 14.0
Calories From Protein: 22.6

Answer 1

CODE :
#include <iostream>
#include <fstream>
#include <string>
#include <cstring>
using namespace std;

struct NutritionData {
char foodName[40];
double servingSize;
double calFromCarb;
double calFromFat;
double calFromProtein;
double totalCalories;
};

//write a single record to file in binary mode
void writeToFile(ofstream &out, const char *name, double size, double carbCal, double fatCal, double protCal)
{
NutritionData n;
strcpy(n.foodName, name);
n.servingSize = size;
n.calFromCarb = carbCal;
n.calFromFat = fatCal;
n.calFromProtein = protCal;
n.totalCalories = n.calFromCarb + n.calFromFat + n.calFromProtein;
out.write((char *)&n, sizeof(n));
}

int main()
{
const char filename[] = "nutri.dat";
ofstream out(filename, ios::binary);

//write the records to file
writeToFile(out, "Apples raw", 110, 50.6, 1.2, 1.0);
writeToFile(out, "Bananas", 225, 186, 6.2, 8.2);
writeToFile(out, "Bread pita whole wheat", 64, 134, 14, 22.6);
writeToFile(out, "Broccoli raw", 91, 21.9, 2.8, 6.3);
writeToFile(out, "Carrots raw", 128, 46.6, 2.6, 3.3);

out.close();

//open the file
ifstream in(filename, ios::binary);in.seekg( 2 * sizeof(NutritionData)); //go to the end of 2nd record i.e where 3rd record begins
NutritionData n;
in.read((char *) &n, sizeof(n));
in.close();cout << "Food Name: " << n.foodName << endl;
cout << "Serving Size: " << n.servingSize << endl;
cout << "Calories Per Serving: " << n.totalCalories << endl;
cout << "Cals From Carb: " << n.calFromCarb << endl;
cout << "Cals From Fat: " << n.calFromFat << endl;
cout << "Cals From Protein: " << n.calFromProtein << endl;

}