Example: Food Calorie Calculator in C

// Food Calorie Calculator
#include <stdio.h>

int main() {
    // Step 1: Declare variables for macronutrient amounts and total calories
    float fat_grams, protein_grams, carb_grams;
    float total_calories;

    // Step 2: Define standard calorie conversion factors per gram
    const int CALORIES_PER_GRAM_FAT = 9;
    const int CALORIES_PER_GRAM_PROTEIN = 4;
    const int CALORIES_PER_GRAM_CARB = 4;

    // Step 3: Prompt user for input for each macronutrient
    printf("--- Food Calorie Calculator ---\n");
    printf("Enter grams of Fat: ");
    scanf("%f", &fat_grams);

    printf("Enter grams of Protein: ");
    scanf("%f", &protein_grams);

    printf("Enter grams of Carbohydrates: ");
    scanf("%f", &carb_grams);

    // Step 4: Calculate calories from each macronutrient
    float fat_calories = fat_grams * CALORIES_PER_GRAM_FAT;
    float protein_calories = protein_grams * CALORIES_PER_GRAM_PROTEIN;
    float carb_calories = carb_grams * CALORIES_PER_GRAM_CARB;

    // Step 5: Calculate total calories
    total_calories = fat_calories + protein_calories + carb_calories;

    // Step 6: Display the results
    printf("\n--- Nutritional Breakdown ---\n");
    printf("Calories from Fat: %.2f\n", fat_calories);
    printf("Calories from Protein: %.2f\n", protein_calories);
    printf("Calories from Carbohydrates: %.2f\n", carb_calories);
    printf("-----------------------------\n");
    printf("Total Calories: %.2f\n", total_calories);

    return 0;
}