Non-function do while loop in C

user_13778311 0
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I'm new to programming and was hoping I could get some help. I'm attempting to create a 'do while' loop in C as part of my CS50 problem sets. I'm attempting to use two different conditions under 'while', but for some reason they are not being recognised. Here's my code

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

int get_height(void);

int main(void)

{
    int height = get_height();
    printf("you picked %i\n", height);
}

int get_height(void)
{
    int height;
    do
    {
        height = get_int("enter height\n");
    }
    while (height > 8 && height < 1);
    return height;
}

I'm trying to force the user to type an integer under 8, but above 0. If I take out either one of the two conditions, that single condition works. If I try to use both conditions however, the code compiles and runs but it doesn't force me to enter a number within the parameters specified. I can just enter any number and it will be accepted. Can anyone help?

EDIT: I'm embarrassed. I misunderstood how AND operators work.

logical-or logical-and cs50 do-while c
3 Answers

Your condition says "continue the loop if height is larger than 8 AND height is smaller than 1". That condition will never be true, so the loop exit after the first iteration.

What you want is "continue the loop if height is larger than 8 OR height is smaller than 1"

while (height > 8 || height < 1);
user_16871190

These are mutually exclusive:

while (height > 8 && height < 1);

You probably want:

while (height > 8 || height < 1);

Now if the value is greater than 8 or smaller than 1, the loop will keep going.

user_124885090

I think that mathematics have not yet found an integer number that can be at the same time less than 1 and greater than 8.

while (height > 8 && height < 1);

It is evident you mean

while (height > 8 || height < 1);

But to make such a condition more clear for yourself it is useful sometimes to write at first the condition for which a number is being searched.

You need a number that lies in the range [1, 8] that is the target number shall satisfy the condition

1 <= height && height <= 8

In this case the condition in the do-while statement will be a negation of the condition above.

while ( !( 1 <= height && height <= 8 ) );

Now if to remove the negation you will have

while ( !( 1 <= height ) || !( height <= 8 ) );

that is equivalent to

while ( 1 > height || height > 8 );

So either use

while ( !( 1 <= height && height <= 8 ) );

pr

while ( 1 > height || height > 8 );
user_28772410
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