n00b tackles another problem set, needs more help :\

Thanks for your patience with me. I know these messages are probably annoying. Thanks for bearing with me.

So my new assignment is as follows:

Quote:

(15 points.) According to the Center for Disease Control (CDC), Body Mass Index (BMI) is a
“reliable indicator of body fatness for most people and is used to screen for weight categories
that may lead to health problems.” An adult’s BMI is a function of his or her weight and
height, the formula for which is

w/h(square)x703

where w is weight in pounds and h is height in inches.

Adults’ weights can be categorized by
BMI per the table below.
BMI Status
< 18.5 Underweight
18.5 – 24.9 Normal
25.0 – 29.9 Overweight
> 29.9 Obese

Write, in a file called bmi.c, a program that first prompts users for their weight and height and then informs them of their BMI and status. Americans tend to think in terms of feet, so let users provide their height in feet plus inches. The aesthetics of your program are largely up to you, but your program must prompt users for input in this order: pounds then feet then inches. Functionally, then, your program must resemble the below. Underlined are some sample inputs.

Weight in pounds: 165
Height (feet): 6
Height (inches): 2
Your BMI is 21.2. You are normal.

As implied by the above, do require that users’ inputs be non-negative; rather than quit upon invalid input, let the user re-try again and again. Also round your program’s floating-point output to one decimal place.

I have read the lecture material repeatedly as well as the notes and I have done my very best with the knowledge I have so far. I have skipped the floating point part because I haven't a clue what to put. Same with the feet to inches conversion.

For the record this won't compile (surprise, I know). This is what I have come up with so far:

Code:

#include <stdio.h> #include <cs50.h> int main(int argc, char * argv[]) { int weight, height, inches, total; printf("Enter your weight in pounds: "); weight = GetInt(); printf("Enter your height in feet (i.e. if you are 6'4, enter 6: "); height = GetInt(); printf("Enter your height in inches (i.e. if you are 6'4, enter 4: "); inches = GetInt(); total=(weight / height * height * 703); if (total < 18.5) printf("You are underweight\n"); else if (total >= 18.5 && total <=24.9) printf("You are normal weight\n"); else if (total >= 25.0 && total <= 29.9) printf("You are overweight\n"); else (total > 29.9) printf("You are obese\n"); return 0; }

Again, I have read everything I can get my hands on before posting this.

Thank you kindly for your help.

PS: I will gladly take hints too. I am not looking to cut corners. I truly want to learn C. Feel free to make me think with some good questions !

Another case of "unnecessary checking":

Code:

if (total < 18.5) printf("You are underweight\n"); else if (total >= 18.5 && total <=24.9)

You are testing to see if the number is less than 18.5, then checking if it's greater or equal to 18.5 in the else-side of the if. How do you think you would get to that else if there was a value less than 18.5?

Also, I would write a function that takes a message string parameter, prints the message, reads an integer, and validates it (must not be negative), repeating the message.

Edit: And you may find that

Code:

total=(weight / height * height * 703);

needs a cast to floating point type, as the values are integers, and weight / height will be an integer value, and a 200 lbs / 6ft (72") would produce 2, not 2.77.

--
Mats

So you need to create your GetInt function. Then I suggest that you take a look at floating point numbers (you must have some kind of course material you can refer to?). You need a floating-point type to store decimals.
Then the assignment says to check for negative numbers. Can't be difficult, can it? What are you having difficulty with?

I guess I'll hit on what others didn't. You have to use a format specifier in the printf() statement to have it display the correct number of decimal places.

printf("%.3f", BMI); would produce a floating point number with three decimal places. I truly don't believe you have looked at all other possible resources.
printf("%.5f", BMI); would print the value of BMI with 5 decimal places.
Doesn't seem that hard does it?

As for not quiting if a - number or invald input is entered. You need a loop.
Three types of loops exist(excluding goto which could achieve a looping process)

You have the for loop, the while loop, and the doWhile loop.

Code:

a for loop is like this for(initialization; control; expression) { code that should be contained inside the loop } a while loop is as this while(control) (i.e wieght < 0) { code here } and the do while do { code here } while(control);

I only hit the basics really (giving you the names of what you need to be googling)
Good luck.

Hi all, and thanks for responding. Please understand, I am a complete beginner. The course is a complete beginner's course. I have zero programming experience. The instructor covered loops, floats, etc. But, he covered them one by one. He didn't show how to put them together to create a program that uses all of them in a sequential manner. The same can be said for the books and resources on the net. Yes, all the info is there, but putting them together is a different story.

Does anyone know where I could find a complete beginner's forum?

StrictlyC: Not sure why you are saying to print decimal places. I don't see where printing any numbers is a requirement here at all. All I need to do is print a string (i.e. "You are underweight") so I 'm not sure how your advice about printing decimals is relevant? As for the loop, I have no idea where/how to put that in here considering any of the numbers entered could be negative. It seems like I would need 3 loops, one for each question that could potentially create a negative number--and that doesn't sound practical.

Elysia: No, the getInt function is already in the cs50.h header

Matsp: I am checking both numbers because these are ranges. See the instructions to the project. To answer your question: I would NOT get to that elseif if the value was less than 18.5, and I would not want to. That is the point.

Code:

#include <stdio.h> #include <cs50.h> int main(int argc, char * argv[]) { int weight, height, inches, total; printf("Enter your weight in pounds: "); weight = GetInt(); printf("Enter your height in feet (i.e. if you are 6'4, enter 6: "); height = GetInt(); printf("Enter your height in inches (i.e. if you are 6'4, enter 4: "); inches = GetInt(); total=(weight / height * height * 703); if (total < 18.5) printf("You are underweight\n"); else if (total >= 18.5 && total <=24.9) printf("You are normal weight\n"); else if (total >= 25.0 && total <= 29.9) printf("You are overweight\n"); else (total > 29.9) printf("You are obese\n"); return 0; }

Is there a complete beginner's forum, anywhere?

My new and improved code!

Ok granted it's still hosed, but with more research I think I improved it a lot.... or maybe not? I still need to figure out how to get the loop in here in case they enter a negative number.. and something about float to accommodate decimals? Errghghh. Help. Is this looking better?

Code:

#include <stdio.h> #include <cs50.h> #define inchesPerFoot 12 int main(int argc, char * argv[]) { /* Collect data from user */ int pounds, feet, inches, totalHeight, weight, total; printf("Enter your weight in pounds: "); pounds = GetInt(); printf("Enter your height in feet (i.e. if you are 6'4, enter 6: "); feet = GetInt(); printf("Enter your height in inches (i.e. if you are 6'4, enter 4: "); inches = GetInt(); /*We now know the user's pounds, feet, and inches. Now we need to get the their total height by putting together the feet and inches they entered */ totalHeight = (feet * inchesPerFoot) + inches; /*Now we have their height and weight and we can calculate their BMI */ total=(weight / totalHeight(2) * 703); /* Now we can tell them about their BMI */ if (total < 18.5) printf("You are underweight\n"); else if (total >= 18.5 && total <=24.9) printf("You are normal weight\n"); else if (total >= 25.0 && total <= 29.9) printf("You are overweight\n"); else (total > 29.9) printf("You are obese\n"); return 0; }

Quote:

Originally Posted by matsp

Another case of "unnecessary checking":

Code:

if (total < 18.5) printf("You are underweight\n"); else if (total >= 18.5 && total <=24.9)

You are testing to see if the number is less than 18.5, then checking if it's greater or equal to 18.5 in the else-side of the if. How do you think you would get to that else if there was a value less than 18.5?

On the other hand, writing it this way shows a clear correspondance between the code and the spec. I don't think the explicitness is hurting anything.

Quote:

Originally Posted by rightbrainer

Ok granted it's still hosed, but with more research I think I improved it a lot.... or maybe not? I still need to figure out how to get the loop in here in case they enter a negative number.. and something about float to accommodate decimals? Errghghh. Help. Is this looking better?

The far easiest way of doing programming the beginning is making a flow chart.
Write down your logic on a paper with arrows that point where to go next.
Then translate it to psuedo code and finally to real code. It's not difficult.
If you want to do it all by yourself, then that is the best kind of advice I can give you. Writing out logic in code is no different than your thinking pattern.
And I know of no function called GetInt.

Elysia, I already told you getInt is in the cs50 header I am including. Here it is for the record:

Code:

int GetInt() { // try to get an int from user while (true) { // get line of text, returning INT_MAX on failure string line = GetString(); if (line == NULL) return INT_MAX; // return an int if only an int (possibly with // leading and/or trailing whitespace) was provided int n; char c; if (sscanf(line, " %d %c", &n, &c) == 1) { free(line); return n; } else { free(line); printf("Retry: "); } } }

When I try to compile this, I get an error. The error is "In function main, called object on line 27 is not a function" . Line 27 is: totalHeight = (feet * inchesPerFoot) + inches;)

Next error is "syntax error before printf on line 38. Line 38 is printf("You are obese\n");

Code:

#include <stdio.h> #include <cs50.h> #define inchesPerFoot 12 int main(int argc, char * argv[]) { /* Collect data from user */ int pounds, feet, inches, totalHeight, weight, total; printf("Enter your weight in pounds: "); pounds = GetInt(); printf("Enter your height in feet (i.e. if you are 6'4, enter 6: "); feet = GetInt(); printf("Enter your height in inches (i.e. if you are 6'4, enter 4: "); inches = GetInt(); /*We now know the user's pounds, feet, and inches. Now we need to get the their total height by putting together the feet and inches they entered */ totalHeight = (feet * inchesPerFoot) + inches; /*Now we have their height and weight and we can calculate their BMI */ total=(weight / totalHeight(2) * 703); /* Now we can tell them about their BMI */ if (total < 18.5) printf("You are underweight\n"); else if (total >= 18.5 && total <=24.9) printf("You are normal weight\n"); else if (total >= 25.0 && total <= 29.9) printf("You are overweight\n"); else (total > 29.9) printf("You are obese\n"); return 0; }

This:

Code:

else (total > 29.9)

should be:

Code:

else

After all, it is everything else.

Quote:

An adult’s BMI is a function of his or her weight and
height, the formula for which is

w/h(square)x703

Also, check your formula carefully and understand why:

Code:

total=(weight / height * height * 703);

is not the same as:

Code:

total=(weight / (height * height) * 703);

hk.. thanks! It compiles and runs! Problem is now that no matter what values I enter it says "you are under weight"

I suspect this is because I am not handling decimal points..?? Problem is, I don't know how. Anything else that could be causing? Latest code:

Code:

#include <stdio.h> #include <cs50.h> #define inchesPerFoot 12 int main(int argc, char * argv[]) { /* Collect data from user */ int pounds, feet, inches, totalHeight, weight, total; printf("Enter your weight in pounds: "); pounds = GetInt(); printf("Enter your height in feet (i.e. if you are 6'4, enter 6: "); feet = GetInt(); printf("Enter your height in inches (i.e. if you are 6'4, enter 4: "); inches = GetInt(); /*We now know the user's pounds, feet, and inches. Now we need to get the their total height by putting together the feet and inches they entered */ totalHeight = (feet * inchesPerFoot) + inches; /*Now we have their height and weight and we can calculate their BMI */ total=(weight / (totalHeight * totalHeight) * 703); /* Now we can tell them about their BMI */ if (total < 18.5) printf("You are underweight\n"); else if (total >= 18.5 && total <=24.9) printf("You are normal weight\n"); else if (total >= 25.0 && total <= 29.9) printf("You are overweight\n"); else printf("You are obese\n"); return 0; }

total will still be an integer value here, so it's unlikely to be 18.5 or 29.9.

--
Mats

Ok now I get that part... so I need to change all INT references to FLOAT (there is also a getFloat function in the cs50.h header). Is this right? What else is now wrong?

Code:

#include <stdio.h> #include <cs50.h> #define inchesPerFoot 12 int main(int argc, char * argv[]) { /* Collect data from user */ float pounds, feet, inches, totalHeight, weight, total; printf("Enter your weight in pounds: "); pounds = GetFloat(); printf("Enter your height in feet (i.e. if you are 6'4, enter 6: "); feet = GetFloat(); printf("Enter your height in inches (i.e. if you are 6'4, enter 4: "); inches = GetFloat(); /*We now know the user's pounds, feet, and inches. Now we need to get their total height by putting together the feet and inches they entered */ totalHeight = (feet * inchesPerFoot) + inches; /*Now we have their height and weight and we can calculate their BMI */ total=(weight / (totalHeight * totalHeight) * 703); /* Now we can tell them about their BMI */ if (total < 18.5) printf("You are underweight\n"); else if (total >= 18.5 && total <=24.9) printf("You are normal weight\n"); else if (total >= 25.0 && total <= 29.9) printf("You are overweight\n"); else printf("You are obese\n"); return 0; }

Getting closer aren't I? Problem now is that all values are coming back "0" so the calculation is not working.

help

Code:

#include <stdio.h> #include <cs50.h> #define inchesPerFoot 12 int main(int argc, char * argv[]) { /* Collect data from user */ float pounds, feet, inches, totalHeight, weight, total; printf("Enter your weight in pounds: "); pounds = GetFloat(); printf("Enter your height in feet (i.e. if you are 6'4, enter 6: "); feet = GetFloat(); printf("Enter your height in inches (i.e. if you are 6'4, enter 4: "); inches = GetFloat(); /*We now know the user's pounds, feet, and inches. Now we need to get their total height by putting together the feet and inches they entered */ totalHeight = (feet * inchesPerFoot) + inches; /*Now we have their height and weight and we can calculate their BMI */ total=(weight / (totalHeight * totalHeight) * 703); /* Now we will print out all the info we have gathered so far */ printf("Your weight was entered as: %d", weight); printf("Your total height is: %d" , totalHeight); printf("Your BMI is: %d", total); /* Now we can tell them about their BMI */ if (total < 18.5) printf("You are underweight\n"); else if (total <=24.9) printf("You are normal weight\n"); else if (total <= 29.9) printf("You are overweight\n"); else printf("You are obese\n"); return 0; }

Try printing out "pounds" and "feet" and "inches" before using them in your calculation, to make sure they're being read correctly. Also, is your calculation actually correct? The parenthesis don't really do anything for you, since multiplication is handled before division anyway.

Quzah.

quzah, thanks. I did that and it shows all zeroes for values

Well then, your GetFloat function isn't working right. Go fix it. :)

Quzah.

For the record there was nothing wrong with the getFloat function. Here is the completed, working bmi program. I am certain there are easier ways to do this rather than spell everything out explicitly like I did, so I welcome the feedback. Either way, I am very proud of this first program I wrote!! :D

For posterity, if you are taking Harvard University's CS50 course, don't cheat and copy this. Even if you're struggling like crazy, just stick with it, and approach it problem by problem and sooner or later you will get it... like I did.. and if I can do this.. ANYONE can do it. I am happy to help anyone out who is struggling with this. Visit my web site and contact me: www.boleroinc.com

Thanks all!!

Mark

Code:

#include <stdio.h> #include <cs50.h> #define inchesPerFoot 12.0 int main(int argc, char * argv[]) { /*First we must declare all the variables we will be using. "Float" tells the computer we will use real numbers.*/ /*We set pounds, feet, and inches to -1 for the negative # validation*/ float pounds=-1, feet=-1, inches=-1, height, bmiHeight, bmi; /* Collect data from user */ do //here we use a DO loop so if negative numbers are entered, the program asks for the value again { printf("Enter your weight in pounds: "); pounds = GetFloat();//here we call the GetFloat function that is in the cs50.h header } while (pounds <= 0); do { printf("Enter your height in feet (i.e. if you are 6'4, enter 6: "); feet = GetFloat(); } while (feet <= 0); do { printf("Enter your height in inches (i.e. if you are 6'4, enter 4: "); inches = GetFloat(); } while (inches <= 0); /*We now know the user's pounds, feet, and inches. Now we need to get their height by adding the feet and inches they entered */ height = (feet * inchesPerFoot) + inches; /* Now we must square their height in inches to get their bmi height */ bmiHeight = (height * height); /* Now we have everything we need to get their BMI */ bmi = (pounds / bmiHeight) * 703.0; /* Now we will print out all the info we have gathered so far */ printf("\nYour weight is: %.1f" , pounds); printf("\nYour height is: %.1f" , height); printf("\nYour BMI is: %.1f" , bmi); /* and tell them their bmi status */ if (bmi < 18.5) printf("\nYou are underweight"); else if (bmi <=24.9) printf("\nYou are normal weight"); else if (bmi <= 29.9) printf("\nYou are overweight\r"); else printf("You are obese"); return 0; }

For the record, when I first approached this problem I was befuddled. I literally had no idea where to start. SO I started with something very simple. And from there I built it out piece by piece. This is what I started with.

Quote:

#include <stdio.h>
#include <cs50.h>

int
main(int argc, char * argv[])
{
int weight, height, inches;
printf("Enter your weight in pounds: ");
weight = GetInt();
printf("Enter your height in feet: ");
height = GetInt();
printf("Enter your height in inches: ");
inches = GetInt();

printf("The sum of %d and %d and %d is %d!\n", weight, height, inches, weight + height + inches);

return 0;

}

It's not complete. It still fails on the last point:

Quote:

As implied by the above, do require that users’ inputs be non-negative; rather than quit upon invalid input, let the user re-try again and again.

(Emphasis mine.)

Ahhh you are good Elysia :) I added loops now and it works!! I have updated the code in prev post

Well done. What could be improved is your indentation, if you want to be a good programmer.

Elysia, thanks for the feedback. I realize the indentation is bad. I will clean it up. Thanks for your help and insight

Quote:

StrictlyC: Not sure why you are saying to print decimal places.
I don't see where printing any numbers is a requirement here at all.
All I need to do is print a string (i.e. "You are underweight") so I 'm not sure how your advice about printing decimals is relevant?

Your original post:

Quote:

Underlined are some sample inputs. <<<<< opps my bad
Weight in pounds: 165
Height (feet): 6
Height (inches): 2
Your BMI is 21.2

Quote:

As for the loop, I have no idea where/how to put that in here considering any of the numbers entered could be negative. It seems like I would need 3 loops, one for each question that could potentially create a negative number--and that doesn't sound practical.

And again I will refer you to my responce

[CODE]

a for loop is like this
for(initialization; control; expression)
{
code that should be
contained inside the loop
}

a while loop is as this

while(control) (i.e wieght < 0)
{
code here
}

and the do while

do
{

code here

} while(control);
[\CODE]

If your not willing to try then give up and stop asking questions I even threw in the I.E. (wieght < 0)
And no you really don't need three seperate loops.

Code:

while (condition1 < 0 && condition2 < 0 && condition3 < 0) { code here; here; as much as you want; }

I will not do your homework/learning assignment for you. Just point you in the right direction.
If your program has a divsion problem in it I'd worry more about division by zero than someone entering a negative number.

Your procress to get bmiHeight could have an answer of 0 if the correct values were entered into the other variables.

It would be annoying to have to re-enter correct information if you just entered something wrong, so a single loop is not something I would recommend.

Quote:

Originally Posted by Elysia

It would be annoying to have to re-enter correct information if you just entered something wrong, so a single loop is not something I would recommend.

Well it would be better in my opinion. Also I would make it so they was a limit on max number of inches you could enter/ and max number of height (no ones over 8 foot are they? 8 foot 24 inches? How about weight? 12000 lbs? If your going to go through all the trouble of making sure the user doesn't enter a negative number cause it's not realistic then may as well. Also inside a loop with all three I would print the values back out and want comfimation all data enter was correct. Accidently entering weight for inches... or something similar It would be even worse having to enter two more things needlessly when you know the result is going to be wrong in the final outcome cause you did a typo at the first prompt.

How to enter 6 foot exactly in your coode? 5foot 12 inches?
also my way you lose a variable inches and feet. (you dont need as many as you still have)

Code:

do { printf("Enter your height in feet (i.e. if you are 6'4, enter 6: "); height = GetFloat(); <<<<<<<<<<<<<<<<<<<<<<< Changed printf("Enter your height in inches (i.e. if you are 6'4, enter 4: "); height = (height * inchesPerFoot) + GetFloat(); } while (height <= 0); completely doing away with this. height = (feet * inchesPerFoot) + inches;

Just for fun:

Code:

printf("Your height is: %.0f feet and %d %s." , (height/12)-.5 , (int)height-((((int) height)/12)*12) , ((int)height-((((int) height)/12)*12)) != 1 ? "inches" : "inch" );

Thanks but way beyond me at this early stage

Quote:

Originally Posted by rightbrainer

Thanks but way beyond me at this early stage

Well hope you at least addressed the problem of not being able to enter a even height
i.e 5 ft., 6 ft. Good luck.

Quote:

Originally Posted by strictlyC

Well it would be better in my opinion. Also I would make it so they was a limit on max number of inches you could enter/ and max number of height (no ones over 8 foot are they? 8 foot 24 inches? How about weight? 12000 lbs? If your going to go through all the trouble of making sure the user doesn't enter a negative number cause it's not realistic then may as well. Also inside a loop with all three I would print the values back out and want comfimation all data enter was correct. Accidently entering weight for inches... or something similar It would be even worse having to enter two more things needlessly when you know the result is going to be wrong in the final outcome cause you did a typo at the first prompt.

How to enter 6 foot exactly in your coode? 5foot 12 inches?
also my way you lose a variable inches and feet. (you dont need as many as you still have)

That may be so, but repeating correct information just because you did a mistake on one is just annoying. It should re-prompt ONLY for the data you enter incorrectly, and optionally prompt at the end if all the data is correct, but NEVER should it ask a user to re-enter information they've already entered correctly. Then we might as well go back to terminating the program if wrong info is entered.