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 4 of 7.

Satish said:   1 decade ago
First We have to convert hexadecimal to Decimal.
Then we have to find the binary value of that.

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.

Kundan Kumar said:   1 decade ago
First you have look what is value of i.
Value of i is 0x80
It means value in Hexadecimal.

So,
Write it's binary in four bit for each digit
For zero(0) 0000.
For eight(8) 1000.

Finally you get this binary in 16-bit 0000 0000 10000 0000.

Now solve this expression i<<1.
Shift one(1) bit after shifting you get this binary
0000 0001 0000 0000 and print it %d(decimal value) i.e 256.

Vinay said:   1 decade ago
i = 0x80 it is in hexadecimal form.
Decimal form of i =8*16^1+0*16^0=128= 00000000 10000000 in binary form.

After i<<1 it becomes 00000001 00000000. Its decimal equivallent is 256.

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.

ANJANI said:   1 decade ago
Thanks a lot. For your nice explanation. I m fully overwhelm.

Chandini said:   1 decade ago
Please explain briefly about this program.

Kuljeet said:   1 decade ago
@Spa- because its an unsigned char value. its range is 0 to 255. hence it can take any value between 0 and 255, which in this case is 80, represented in hexadecimal form.

Spa said:   1 decade ago
Why everyone taking for char 2bytes. ? can any one explain me.

Sumit said:   1 decade ago
Nikita its not << operator , which converts char to int , its %d which makes changes with c , try to use %c it will give blank as , Ascii value of NULL is 0


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