[C언어 #31_2] 비만도 (BMI) 계산

C언어 비만도 (BMI) 계산 프로그램

 

 

 

키 (m), 몸무게 (㎏) 터미널로 문자열 입력하여 BMI 계산 및 분류

/* Classify BMI */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <ctype.h>
 
// Use Integer constants to represent classes BMI
enum { Underweight, Normal, Overweight, Obese, Invalid };
 
// Check input
bool isValid(int n, const char input[]) {
    int count = 0;
    for (int i = 0; input[i] != '\0'; i++) {
        if (!isdigit(input[i])) {
            if (input[i] == '.') {
                count += 1;
                if (count > 1) return false;
            } else {
                return false;
            }
        }
    }
    return true;
}
 
// Convert string to double
double convert(int n, const char input[]) {
    return isValid(n, input) ? atof(input) : -1;
}
 
// Check invalid height or weight
bool isInvalid(double height, double weight) {
    bool b = (height >= 3.5 || height <= 0.2 || weight >= 350 || weight <= 15);
    return b;
}
 
// Calculate BMI: weight(kg) ÷ height²(m)
double getBmi(double height, double weight) {
    double bmi;
    if (isInvalid(height, weight)) bmi = -1;
    else bmi = weight / (height * height);
    return bmi;
}
 
// Classify BMI
int classifyBmi(double bmi) {
    if (bmi < 0) return Invalid;
    if (bmi < 18.5) return Underweight;
    if (bmi < 25) return Normal;
    if (bmi < 30) return Overweight;
    else return Obese;
}
 
// Print if input is invalid
void printInvalid(int n) {
    if (n == -1) printf("Invalid input!!\n");
}
 
// Print BMI, BMI class
void print(double bmi, int bmiClass) {
    switch (bmiClass) {
        case Obese: printf("BMI: %.4f - Obese\n", bmi); break;
        case Overweight: printf("BMI: %.4f - Overweight\n", bmi); break;
        case Normal: printf("BMI: %.4f - Normal\n", bmi); break;
        case Underweight: printf("BMI: %.4f - Underweight\n", bmi); break;
        case Invalid: printInvalid(bmi); break;
    }
}
 
// Print height, weight
void printHW(double height, double weight) {
    printf("Height: %.4f (m), Weight: %.4f (kg)\n", height, weight);
}
 
// Print height, weight, BMI, BMI class
void printResult(double height, double weight, double bmi, int bmiClass) {
    switch (bmiClass) {
        case Invalid: printInvalid(bmi); break;
        case Obese:
            printHW(height, weight);
            printf("BMI: %.4f - Obese\n", bmi); 
            break;
        case Overweight:
            printHW(height, weight);
            printf("BMI: %.4f - Overweight\n", bmi); 
            break;
        case Normal:
            printHW(height, weight);
            printf("BMI: %.4f - Normal\n", bmi); 
            break;
        case Underweight:
            printHW(height, weight);
            printf("BMI: %.4f - Underweight\n", bmi); 
            break;
    }
}
 
// Get string input
void getInputs(char height[], char weight[]) {
    printf("Input Height (m): ");
    scanf("%s", height);
    printf("Input Weight (kg): ");
    scanf("%s", weight);    
}
 
int main() {
    setbuf(stdout, NULL);
 
    char h[20];         // Array for string input height
    char w[20];         // Array for string input weight
    getInputs(h, w);    // Get input from terminal
 
    // Convert and get height, weight
    double height = convert(strlen(h), h);
    double weight = convert(strlen(w), w);
 
    // Get BMI rating, class from height, weight
    double bmi = getBmi(height, weight);
    int bmiClass = classifyBmi(bmi);
    
    // Print result
    printResult(height, weight, bmi, bmiClass);
}