What is x 1 and x 1

Question

I am trying to do assignment   Find the number of bits in an unsigned integer data type without using the sizeof   function    And my design is to convert the integer to bits and then to count them  For ex  10 is 1010 and 5 is 101  Converting integer to a bit representation shows something like this   do        Vec push back  x  amp  1       while   x  gt  gt   1      I don t want to just copy paste stuff  When I use F-10 I see what  x  amp  1  is doing but I don t know it is name or how it does its job compare something    Also I know  gt   which  greater than or equal  but what is x  gt  gt   1   Note  The marked duplicate is a JavaScript and not C

User · Accepted Answer

These are Bitwise Operators  reference    x  amp  1 produces a value that is either 1 or 0  depending on the least significant bit of x  if the last bit is 1  the result of x  amp  1 is 1  otherwise  it is 0  This is a bitwise AND operation   x  gt  gt   1 means  set x to itself shifted by one bit to the right   The expression evaluates to the new value of x after the shift   Note  The value of the most significant bit after the shift is zero for values of unsigned type  For values of signed type the most significant bit is copied from the sign bit of the value prior to shifting as part of sign extension  so the loop will never finish if x is a signed type  and the initial value is negative

User · Answer

In addition to the answer of  dasblinkenlight  I think an example could help  I will only use 8 bits for a better understanding      x  amp  1 produces a value that is either 1 or 0  depending on the least   significant bit of x  if the last bit is 1  the result of x  amp  1 is 1    otherwise  it is 0  This is a bitwise AND operation    This is because 1 will be represented in bits as 00000001  Only the last bit is set to 1  Let s assume x is 185 which will be represented in bits as 10111001  If you apply a bitwise AND operation on x with 1 this will be the result   00000001 10111001 -------- 00000001   The first seven bits of the operation result will be 0 after the operation and will carry no information in this case  see Logical AND operation   Because whatever the first seven bits of the operand x were before  after the operation they will be 0  But the last bit of the operand 1 is 1 and it will reveal if the last bit of operand x was 0 or 1  So in this example the result of the bitwise AND operation will be 1 because our last bit of x is 1  If the last bit would have been 0  then the result would have been also 0  indicating that the last bit of operand x is 0   00000001 10111000 -------- 00000000      x  gt  gt   1 means  set x to itself shifted by one bit to the right   The   expression evaluates to the new value of x after the shift   Let s pick the example from above  For x  gt  gt   1 this would be   10111001 -------- 01011100   And for left shift x  lt  lt   1 it would be   10111001 -------- 01110010   Please pay attention to the note of user  dasblinkenlight  in regard to shifts

User · Answer

It is similar to x    x  gt  gt  1     operand1  operator   operand2   implies   gt     operand1   operand1  operator  operand2     It shifts the binary value of x by one to the right   E g    int x 3        binary form  011   x   x  gt  gt  1     zero shifted in from the left  1 shifted out to the right                 x 1  binary form  001

User · Answer

n  amp  1  will check if  n  is odd or even  this is similar to  n 2    In case  n  is odd  n  amp  1  will return true 1   Else it will return back false 0     The   gt  gt   in  n gt  gt  1  is a bitwise operator called  quot Right shift quot   this operator will modify the value of  n   the formula is   n  gt  gt   m    gt   n   n gt  gt m    gt   n   n 2 m   Go through GeeksforGeek s article on  quot Bitwise Operator s quot   recommended

User · Answer

x  amp  1 is equivalent to x   2   x  gt  gt  1 is equivalent to x   2  So  these things are basically the result and remainder of divide by two

[c++] What is (x & 1) and (x >>= 1)?

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