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What is the output of this c code?

What is the output of this c code?

theAvinash

@theavinash-DAs260 • Oct 26, 2024

Oct 26, 2024

1.5K

#include<stdio.h>
#include<conio.h>
int main()
{

int a=0.7;
clrscr();
if(a==0.7)
printf("equal");
else
printf("not equal");
getch();
}
.....................................
make required changes to run on linux...
also answer this
#include<stdio.h>
#include<conio.h>
int main()
{

float a=0.7;
clrscr();
if(a==0.7)
printf("equal");
else
printf("not equal");
getch();
}

0 16

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simplycoder

@simplycoder-NsBEdD • Sep 30, 2012

Did it compile?
I should throw exception on int a=0.7;

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theAvinash

@theavinash-DAs260 • Sep 30, 2012

yes dude

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simplycoder

@simplycoder-NsBEdD • Sep 30, 2012

What compiler are you using?
Prefer DevC++ or Code blocks.(See the list of compilers they are using.)
Please donot use Turbo C/C++.

As well, conio is not a standard c library function.

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VIJAYSY

@vijaysy-L0Tg5s • Sep 30, 2012

out put is -not equal
because in first case data type of a is int so,a is stored as 0;
in second case even data type of a is float,but internally a is stored as 0.699999

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theAvinash

@theavinash-DAs260 • Sep 30, 2012

how you can say in 2nd case a is stored as 0.699999?

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theAvinash

@theavinash-DAs260 • Sep 30, 2012

in 2 nd case.
i think 0.7 is treated as double..so the if condition fails...
if we type cast 0.7 to float as (float)0.7.... the answer is equl

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simplycoder

@simplycoder-NsBEdD • Sep 30, 2012

Avinash Wagholein 2 nd case.
i think 0.7 is treated as double..so the if condition fails...
if we type cast 0.7 to float as (float)0.7.... the answer is equl
This can be justified by the computer organization-architecture.
Read how floats are saved in computer. You would also require some knowledge on mantissa-exponent form.
Try to represent 0.7 in binary, you would get the answer.

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grsalvi

@grsalvi-7IhIh1 • Sep 30, 2012

1st case is clear
but for 2nd case a is getting stored as .700000 still why 'not equal' getting printed ?

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VIJAYSY

@vijaysy-L0Tg5s • Sep 30, 2012

yes a is stored as 0.700000
(up to my knowledge)
the 0.7 which is used to compare with 'a' is taken as double
you can check with sizeof(0.7) it shows 8.
if you type cast 0.7 to float it will convert to float ,
the data type of 0.7(which is used to compare with a) is not in hands of user,

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sulochana anand

@sulochana-anand-OrGmKr • Sep 30, 2012

the answer is not equal.because int data type only stores without decimal values.so it will not undetand first part and controll will move to else part.

0
sulochana anand

@sulochana-anand-OrGmKr • Sep 30, 2012

its a type of logical error.

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grsalvi

@grsalvi-7IhIh1 • Oct 1, 2012

Okay...
But suppose float a=0.7; (compiler stores : a=0.700000)
And double b=0.7; (compiler stores : b=0.70000000000000)

Still they should be equal.And why difference between a and b is not zero?
Any idea what way the difference is getting calculated?

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VIJAYSY

@vijaysy-L0Tg5s • Oct 1, 2012

i guess,
out put is 0.000000 ,0,or 0.00000000000000 depends on format specifiers used in printf function ,while subtraction implicit type conversation will take place ,a is converted to double,

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sulochana anand

@sulochana-anand-OrGmKr • Oct 1, 2012

we know that when we declare any data type our system allocate space in memory accordingly.double and float both support decimal values.but only size is diffrent.float occupy 4 bytes and double 8 bytes.if we would store value which eceeds 4 byte in float it will give an error.but 0.7 is limited value so it will give right answer.

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theAvinash

@theavinash-DAs260 • Oct 1, 2012

Computers use a binary (0's and 1's) system to store decimal numbers. This leads to some inaccuracy, since some decimal values can't be stored exactly in binary....0.7 is stored as the value 0.69999999.Since that value isn't 0.7, the condition fails..

The float function takes care of this problem -
float(0.7)
it rounds the value 0.69999999 to 0.7. Many decimal values are stored accurately in binary, for example 0.5, but many are not.

its good to use the float function...

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grsalvi

@grsalvi-7IhIh1 • Oct 2, 2012

Avinash WagholeComputers use a binary (0's and 1's) system to store decimal numbers. This leads to some inaccuracy, since some decimal values can't be stored exactly in binary....0.7 is stored as the value 0.69999999.Since that value isn't 0.7, the condition fails..

The float function takes care of this problem -
float(0.7)
it rounds the value 0.69999999 to 0.7. Many decimal values are stored accurately in binary, for example 0.5, but many are not.

its good to use the float function...
I told above that there is no problem during storage as seen during debugging.
The problem is difference between a and b is not zero,hence machine says they are unequal.

see below,

float a=0.7 (compiler stores 0.700000)
double b=0.7 (compiler stores 0.70000000000000)

During debugging : a-b=-9.2559631349318e+061

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