Question

Design a program that asks for the number of fat grams and calories in a food item. Validate the input as follows:
Make sure the number of grams and calories is not less than 0.
According to nutritionist formulas, the number of calories cannot exceed fat grams x 9. Make sure that the number of calories entered is not greater than fat grams x 9.
Once correct data has been entered, the program should calculate and display the percentage of calories that come from fat. Use the following formula:
Percentage of calories from fat =( fat grams x 9) ÷ calories
Some nutritionist classify a food as "low fat" if less than 0.3, the program should display a message indicating the food is low in fat.

Answer 1

#include <iostream>
using namespace std;

int main() {
  
   double fatGrams,calories,caloriesPer;
  
   do
   {
   cout<<"\nEnter the number of fat grams : ";
   cin>>fatGrams;
   if(fatGrams < 0)
   cout<<"\nFat grams should not be less than 0 . Enter again";
   }while(fatGrams < 0);
  
   do
   {
   cout<<"\nEnter the number of calories : ";
   cin>>calories;
   if(calories < 0)
   cout<<"\nCalories should not be less than 0 . Enter again";
   }while(calories < 0);
  
  
caloriesPer = (fatGrams*9)/calories;
cout<<"\nPercentage of calories from fat : "<<caloriesPer;

if(caloriesPer <0.3)
cout<<"\nFood is low in fat";

  
   return 0;
}

Output:

Enter the number of fat grams : -7
Fat grams should not be less than 0 . Enter again
Enter the number of fat grams : 6
Enter the number of calories : 100
Percentage of calories from fat : 0.54

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