Thread: simple if statment need help

i cant figure out this if statment

It is driving me nuts

all im trying to do is take in for floats

evaluate them and print which one is bigger

im very new to C

for some reason the first half works but the second half doesnt

For some reason the bottom part that says print integer is passing its criteria and keeps printing integer 2 out when integer 2 clearly is not less the integer 1

im just giving it the input "1 2 3 4 "

can someone please tell me why when given "1 2 3 4" it thinks my else if for integer 2 is true and is printing

It is clearly false. I used && gates so all factors must be true for it to print. obviously it fails so why and how could it be printing

Code:

#include <stdio.h>
#include <stdlib.h>


int main()
{

    float integer_1;//first number
    float integer_2;//second number
    float integer_3;//3rd number
    float integer_4;//4th number


printf("this program displays the largest and smallest number entered by the user");

printf("Please enter the 4 integers you would like to use with a space between them xx xx xx xx");

scanf("%f  %f  %f  %f",&integer_1 ,&integer_2  ,&integer_3  ,&integer_4);//store the value of user input
                                                                        // into the correct variable location
printf("%.1f %.1f %.1f %.1f\n",integer_1,integer_2,integer_3,integer_4);// print the variable on the screen to confirm they are taken in correctly. Just for testing




if (integer_1>integer_2&&integer_1>integer_3&&integer_1>integer_4)//logical system to answer the question is integer 1 the biggest. If it does not pass to any of the criteria is should move on to next line
    printf("Largest%f\n",integer_1);//if it pass print largest value

    else

    if (integer_1<integer_2&&integer_1<integer_3&&integer_1<integer_4);//test to see if integer 1 is possibly the smallet value
    printf("smallest  %.1f\n",integer_1);//if it is print it on the screen



printf("%.2f   %.2f   %.2f   %.2f\n\n\n",integer_1,integer_2,integer_3,integer_4);//just for testing

if ((integer_2>integer_1)&&(integer_2>integer_3)&&(integer_2>integer_4))//logical system to find out if integer 2 is the greatest value
    printf("Largest%f\n",integer_2);//if it is print it

    else

    if (integer_2<integer_1&&integer_2<integer_3&&integer_2<integer_4);//logical system to see if integer 2 is smallest, if it is print it. If no criteria is met move on.
    {printf("smallest  %.1f\n",integer_2);}//this one is the problem i speak of! it keeps printing this off when its FALSE





















return(0);

}

Instead of this "logical scrum" you have going, do it the simple way.

Code:

int small, large;
small = large = integer_1;

if(small < other integers)
   small == that integer # value

if(large > other integers)
   large == that integer # value

printf(Smallest: %d        Largest: %d",small, large);

It's such a simple word really -- row. :rofl:

Your formatting/indentation needs work. Make sure you have an editor that has an auto-indent feature, it would help you catch your error here. On lines 30 and 42 you have an errant semicolon at the end of your if. That means the following statement is always executed.

Originally Posted by Adak

Instead of this "logical scrum" you have going, do it the simple way.

Code:

int small, large;
small = large = integer_1;

if(small < other integers)
   small == that integer # value

if(large > other integers)
   large == that integer # value

printf(Smallest: %d        Largest: %d",small, large);

It's such a simple word really -- row. :rofl:

i would love to do it an easier way
if u have a second could you explain a bit more what you have going on

why in the begining you have small-large=intege1?

i dont understand that

Originally Posted by anduril462

Your formatting/indentation needs work. Make sure you have an editor that has an auto-indent feature, it would help you catch your error here. On lines 30 and 42 you have an errant semicolon at the end of your if. That means the following statement is always executed.

right because it has been terminated

im using codeblocks

im very new to programming im a math major
so im just learning what i can and cant do

Thanks for the catch there. Do you think this will work if i continue on?

Im sure you get the idea of what is 2 come next

same sequnce but with integer 3 and then again integer 4

Do you think that would work?
im sure there are easier ways but i sure dont know them

Think of it as a point of reference. Say you only had 1 value, and your program had to find the smallest and the largest value. What would that be?

Correct! The very first value, for both.

Work it through with some coins on your desk, and see if it works.

Thanks for the help guys
ill keep plugging away at it

see if i can make any more progress

i think i got it!
it was the semi colon

the track i was on was working might not be simplest or prettiest but it does work i think atleast lol

Code:

#include <stdio.h>
#include <stdlib.h>


int main()
{

    float integer_1;//first number
    float integer_2;//second number
    float integer_3;//3rd number
    float integer_4;//4th number


printf("this program displays the largest and smallest number entered by the user");

printf("Please enter the 4 integers you would like to use with a space between them xx xx xx xx");

scanf("%f  %f  %f  %f",&integer_1 ,&integer_2  ,&integer_3  ,&integer_4);//store the value of user input
                                                                        // into the correct variable location
printf("%.1f %.1f %.1f %.1f\n",integer_1,integer_2,integer_3,integer_4);// print the variable on the screen to confirm they are taken in correctly. Just for testing




if (integer_1>integer_2&&integer_1>integer_3&&integer_1>integer_4)//logical system to answer the question is integer 1 the biggest. If it does not pass to any of the criteria is should move on to next line
    printf("Largest%f\n",integer_1);//if it pass print largest value

    else

    if (integer_1<integer_2&&integer_1<integer_3&&integer_1<integer_4)//test to see if integer 1 is possibly the smallet value
    printf("smallest  %.1f\n",integer_1);//if it is print it on the screen



printf("%.2f   %.2f   %.2f   %.2f\n\n\n",integer_1,integer_2,integer_3,integer_4);//just for testing

if ((integer_2>integer_1)&&(integer_2>integer_3)&&(integer_2>integer_4))//logical system to find out if integer 2 is the greatest value
    printf("Largest%f\n",integer_2);//if it is print it

    else

    if (integer_2<integer_1&&integer_2<integer_3&&integer_2<integer_4)//logical system to see if integer 2 is smallest, if it is print it. If no criteria is met move on.
    {printf("smallest  %.1f\n",integer_2);}//this one is the problem i speak of! it keeps printing this off when its FALSE




if ((integer_3>integer_1)&&(integer_3>integer_2)&&(integer_3>integer_4))//logical system to find out if integer 2 is the greatest value
    printf("Largest%f\n",integer_3);//if it is print it

    else

    if (integer_3<integer_1&&integer_3<integer_2&&integer_3<integer_4)//logical system to see if integer 2 is smallest, if it is print it. If no criteria is met move on.
    {printf("smallest  %.1f\n",integer_3);}//this one is the problem i speak of! it keeps printing this off when its FALSE




if ((integer_4>integer_1)&&(integer_4>integer_2)&&(integer_4>integer_3))//logical system to find out if integer 2 is the greatest value
    printf("Largest%f\n",integer_4);//if it is print it

    else

    if (integer_4<integer_1&&integer_4<integer_2&&integer_4<integer_3)//logical system to see if integer 2 is smallest, if it is print it. If no criteria is met move on.
    {printf("smallest  %.1f\n",integer_4);}//this one is the problem i speak of! it keeps printing this off when its FALSE















return(0);

}

Yeah, your solution isn't the easiest/prettiest/most efficient, but it should work. Of course, you're going to test this thoroughly before submitting it to make sure, right?

The reason your code is not the best is that it doesn't scale as well as Adak's (though no solution is really scalable without an array). Imagine how long your if conditions would be if you had 10 integers. Not only that, you compare each number against each other, twice (once for smallest, once for largest). For N integers, that's N*(N-1) for smallest and another N*(N-1) for largest. That's a lot of unnecessary comparisions. It never remembers anything from previous comparisons.


Adak's solution looks at each number in turn, and remembers the smallest and largest number it's seen so far. It only uses N-1 comparisons for each of smallest and largest. That is the same concept you would use if you had to do this for an array of unknown size. Note that the conditions in Adak's example are backwards, it should be:

Code:

small = large = integer_1;  // look at integer_1, so far it's the smallest and largest number we've seen


if (integer_2 < small)
    small = integer_2;  // integer_2 is smaller than anything so far, record it as the smallest


// similar for largest and for integer_3 and integer_4

Originally Posted by anduril462

Yeah, your solution isn't the easiest/prettiest/most efficient, but it should work. Of course, you're going to test this thoroughly before submitting it to make sure, right?

The reason your code is not the best is that it doesn't scale as well as Adak's (though no solution is really scalable without an array). Imagine how long your if conditions would be if you had 10 integers. Not only that, you compare each number against each other, twice (once for smallest, once for largest). For N integers, that's N*(N-1) for smallest and another N*(N-1) for largest. That's a lot of unnecessary comparisions. It never remembers anything from previous comparisons.


Adak's solution looks at each number in turn, and remembers the smallest and largest number it's seen so far. It only uses N-1 comparisons for each of smallest and largest. That is the same concept you would use if you had to do this for an array of unknown size. Note that the conditions in Adak's example are backwards, it should be:

Code:

small = large = integer_1;  // look at integer_1, so far it's the smallest and largest number we've seen


if (integer_2 < small)
    small = integer_2;  // integer_2 is smaller than anything so far, record it as the smallest


// similar for largest and for integer_3 and integer_4

Thanks yes it does work. I apprecaite the help and suggestions
I would like to make it as nice as possible but bot truly unerstand what we are doing above so im gonna spend some time on.
For now, my ugly way works for 4 digits. lol

I apprecaite the help greatly.