Thread: Going further in C + Comments on simple program

Hey there everyone!
I'm quite new to the C language. I have finished a book that teaches the C basics (syntax and basic concepts.)
I'm not sure what to do now, but I did read you have to read other people's source code, and things like that.
But I'm not sure where to start.

I'de be grateful if you'd point out the right direction to take.

I uploaded a simple terminal program I coded that calculates BMI.

Upd8 Okey dokey laserlight!

Code:

//
//  main.c
//  bmiCalc
//
//  Created by Ishraq on 2/27/15.
//  Copyright (c) 2015 Ishraq. All rights reserved.
//


#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <stdbool.h>


int main(int argc, const char * argv[]) {
    
    char  unitChoiceWeight;
    char  unitChoiceHeight;
    float weight;
    float height;
    float bmi;
    
    printf("\n© Ishraq ( doCode() )");
    printf("\n\n| __BMI Calculator__ |\n\n");
    
    sleep(1);
    
    printf("Choose which unit you want to enter your _weight_ in from the following list.\n\n");
    printf("________________________________________________\n\n");
    printf("Kilograms (kg) - Type in _'kg'_ for kilograms\n");
    printf("Pounds    (lb) - Type in _'lb'_ for pounds\n");
    printf("Stones    (st) - Type in _'st'_ for stones\n");
    printf("________________________________________________\n\n");
    
    sleep(2);
    
    printf("Enter your choice here > ");
        
    scanf("%s", &unitChoiceWeight);


    if (!strcasecmp(&unitChoiceWeight, "kg")) {
        printf("You have chosen kilograms.\n\n");
    } else if (!strcasecmp(&unitChoiceWeight, "lb")) {
        printf("You have chosen pounds.\n\n");
    } else if (!strcasecmp(&unitChoiceWeight, "st")) {
        printf("You have chosen stones.\n\n");
    } else {
        printf("You have entered an invalid value.");
        return 0;
    }
    
    printf("Now, enter your _weight_ here > ");
    scanf(" %f", &weight);
    
    if (!strcasecmp(&unitChoiceWeight, "lb")) {
        printf("You claim to weigh %2.f lb, which is ", weight);
        weight /= 2.2046;
        printf("%.2f kg. \n\n\n", weight);
    } else if (!strcasecmp(&unitChoiceWeight, "st")) {
        printf("You claim to weigh %.2f st, which is ", weight);
        weight = (weight*14)/2.2046;
        printf("%.2f kg. \n\n\n", weight);
    } else {
        printf("You claim to weigh %.2f kg.\n\n\n", weight);
    }


    
    sleep(1);
    
    printf("Choose which unit you want to enter your _height_ in from the following list.\n\n");
    
    sleep(2);
    
    
    sleep(1);
    printf("________________________________________________\n\n");
    printf("Meter       (m)  - Type in _'m '_ for meters\n");
    printf("Inch        (in) - Type in _'in'_ for inches\n");
    printf("Foot        (ft) - Type in _'ft'_ for feet\n");
    printf("Millimeter  (mm) - Type in _'mm'_ for millimeters\n");
    printf("________________________________________________\n\n");
    sleep(1);
    
    printf("Enter your choice here > ");
    
    scanf("%s", &unitChoiceHeight);
    
    if (!strcasecmp(&unitChoiceHeight, "m")) {
        printf("You have chosen meters.\n\n");
    } else if (!strcasecmp(&unitChoiceHeight, "in")) {
        printf("You have chosen inches.\n\n");
    } else if (!strcasecmp(&unitChoiceHeight, "ft")) {
        printf("You have chosen feet.\n\n");
    } else if (!strcasecmp(&unitChoiceHeight, "mm")){
        printf("You have chosen millimeters.\n\n");
    } else {
        printf("You have entered an invalid value.");
        return 0;
    }
    
    printf("Now, enter your _height_ here > ");
    scanf(" %f", &height);
    
    
    if (!strcasecmp(&unitChoiceHeight, "in")) {
        printf("You claim to have a height %2.f in, which is ", height);
        height /= 39.370;
        printf("%.2f m. \n\n\n", height);
    } else if (!strcasecmp(&unitChoiceHeight, "ft")) {
        printf("You claim to have a height %.2f ft, which is ", height);
        height /= 3.2808;
        printf("%.2f m. \n\n\n", height);
    }else if (!strcasecmp(&unitChoiceHeight, "mm")) {
        printf("You claim to have a height %.2f mm, which is ", height);
        height /= 1000.0;
        printf("%.2f m. \n\n\n", height);
    } else {
        printf("You claim to have a height of %.2f m.\n\n\n", height);
    }
    sleep(1);
  
    for (int flair = 0; flair < 3; flair++) {
        printf("Processing your BMI...\n");
        sleep(1);
    }
    
    printf("\n");
    
    printf("And your BMI is...");
    sleep(1);
    bmi = (weight) / (height*height);
    sleep(1);
    printf("%f!\n\n", bmi);
    
    if (bmi <= 18.5) {
        printf("You are underweight.\n\n");
    } else if ((bmi >= 18.8) && (bmi <= 25)) {
        printf("You have a normal weight.\n\n");
    } else if ((bmi >= 25.5) && (bmi <= 30)) {
        printf("You are overweight.\n\n");
    } else if (bmi >= 30) {
        printf("You are obese.\n\n");
    }
    
    
}
    




//      Give weight in kilograms
///         (divided by)
//      Height in meters to the power 2
//Underweight = <18.5
//Normal weight = 18.5–24.9
//Overweight = 25–29.9
//Obesity = BMI of 30 or greater

The attached file can be opened using the terminal.

If your program is small and simple enough, I suggest that you post it directly within [code][/code] bbcode tags as people may not be so inclined to download and open your zip archive.

Code:

    if (bmi <= 18.5) {
        printf("You are underweight.\n\n");
    } else if ((bmi >= 18.8) && (bmi <= 25)) {
        printf("You have a normal weight.\n\n");
    } else if ((bmi >= 25.5) && (bmi <= 30)) {
        printf("You are overweight.\n\n");
    } else if (bmi >= 30) {
        printf("You are obese.\n\n");
    }

An BMI of 30 has no clear meaning in you program.
And, I have no idea what you want 25.1 thru 25.4 to be.

I suggest using constants or defines instead of literal numbers for the BMI values.


Tim S.

I used this website as reference.

Calculate Your BMI - Standard BMI Calculator

I suggest using constants or defines instead of literal numbers for the BMI values.

Will consider.

....and the right direction to take?

I wish to make software applications, and the likes.
E.g. A program that makes a bootable Linux USB. I wanted to try this one, but it is too advanced for me, at this stage.

The best way to learn is to practice, and to keep learning new techniques, functions, ect. Work your way through these tutorials and take a look at this site.

Originally Posted by doCode()

I wish to make software applications, and the likes.
E.g. A program that makes a bootable Linux USB. I wanted to try this one, but it is too advanced for me, at this stage.

You probably know this, but Linux programs are generally published with source code so you can read them. This includes the popular programs that write the bootloaders (e.g. Grub).

There is an online manual called "Linux from Scratch" which provides step-by-step instructions of how to build a functioning, bootable Linux system using only the source code. If this topoic is interesting to you it might be worth a look.

Originally Posted by doCode()

That Eternally Confuzzled - Home site looks good!

It is the homepage of Prelude, one of the members here (though admittedly one who has not posted for quite some time)

E.g. A program that makes a bootable Linux USB. I wanted to try this one, but it is too advanced for me, at this stage.

Any ideas on this, laserlight?

Originally Posted by doCode()

I would also like some books on C, books that cover the stuff you have to learn and practice after finishing a beginners book on C.

Conveniently enough we have a C Book Recommendations thread.

Originally Posted by doCode()

I meant a program like UNetbootin - Homepage and Downloads

Check on the bottom of the FAQ page. It links to the source code and instructions on how to compile it.