C Programming - Bitwise Operators - Discussion

Discussion Forum : Bitwise Operators - Find Output of Program (Q.No. 5)
5.
What will be the output of the program?
#include<stdio.h>

int main()
{
    unsigned char i = 0x80;
    printf("%d\n", i<<1);
    return 0;
}
0
256
100
80
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
65 comments Page 2 of 7.

Chandan Kumar said:   10 years ago
@Abhinav.

No, its not correct. 0X80 is a hexadecimal number, and for hexadecimal number you have to convert nibble by nibble.

For example:

0X80 --------> two nibbles 8 0.

1000 0000.

0X 75 -------> 7 5.

0111 0101.

Although, you are right if it were decimal number.

For example:

80 ----------> 01010000.

"0X" makes it hexadecimal.

Nagendra said:   9 years ago
// 1

#include<stdio.h>

int main()
{
unsigned char i = 0x80;
printf("%d\n", i<<1);
return 0;
}
Here output 256.

// 2
#include<stdio.h>

int main()
{
unsigned char i = 0x80;
i=i<<1;
printf("%d\n", i);
return 0;
}
Here output 0.

* The diff is assignment of variable i.
(4)

Jay said:   1 decade ago
#include<stdio.h>

int main()
{
char i=0x04;
char k=0x80;
printf("%d",i<<6);
printf("%d",k<<1);

return 0;
}

Output of first print statement is 256 while for other it is -256 how?

Sandeep Kumar said:   8 years ago
#include<stdio.h>

int main()
{
unsigned char i = 0x80;
i=i<<1;
printf("%d\n", i);
return 0;
}

In this case, also typecast operation is performed but final data is stored in 8 bit so the output is 0.
(8)

Adam said:   10 years ago
#include<stdio.h>

int main()
{
unsigned char i = 0x80;
int a=i<<1;
unsigned long b=a;
unsigned char c=b;
printf("%d\n",c);
b=b>>1;
c=b;
printf("%d\n",c);
return 0;
}

Try this.

Mayur said:   1 decade ago
int main()
{
unsigned char i = 0x80;
printf("%d\n", i<<1);
return 0;
}
i=0x80 means 0000 1000 0000
After <<(1 bit shift left) It will become
0001 0000 0000 that means 256.

Sutendra mirajkar said:   1 decade ago
#include<stdio.h>

int main()
{
unsigned char i = 0x80;
i=i<<1;
printf("%d %d %d\n", i);
return 0;
}

Then the output of i is zero can anyone explain why is it so?

Sachin mishra said:   1 decade ago
Here it is given unsigned char that's why we have taken 2 byte.

The hex representation of 80 is 1000 0000.

i = 0000 0000 1000 0000.

Left shift by 1.

We get 1= 0000 0001 0000 0000 = 256 as result.

Mladen Saldanha said:   7 months ago
if were a larger type (e.g., int), 0x80 << 1 would be 256 (binary 100000000).
But the unsigned char is 8-bit, so the overflow bit is discarded, leaving 00000000 (0).
So, I think answer is 0

RajaMohan said:   1 decade ago
Step 1 :

First convert the Hexadecimal into decimal
0x80 ---> 16*8=128.

Step 2 :

Then use bit-wise operation left shift.
128*pow(2,1).
Here 1 indicates the value after left shift.


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