A brief analysis of C + + shift operation and binary conversion

The shift operations include "logical Shift" (logical shift) and "arithmetic Shift" (arithmetic shift).

Logical shift: bit discarded, vacant bit (vacant bit) filled with 0.

Arithmetic shift: The bit discarded, the vacant bit (vacant bit) is filled with "sign bit", so it is generally used in the right-shift operation.

In C + +, integers are divided into two symbols and unsigned numbers. For these two numbers do the left shift and right shift operations. Slightly different:

1, assume that the unsigned number, whether left or right shift is a "logical shift." example, the result of left shift and right shift operation for unsigned number 179 is the complement 0 operation;

2 . Assume that there are signed numbers. To move left, the "logical shift" is the same as the left shift of the unsigned number. Assuming that you do a right-shift operation, the "arithmetic shift" is done.

Finally, this paper gives the recursive working mechanism legend of decimal number conversion to binary. For example, the following

The 10 binary number is converted to a binary number, which is a continuous process in addition to 2:

Divide the number to be converted by 2 to get the quotient and remainder.

Continue dividing the quotient by 2 until the quotient is 0. Finally, the whole remainder is arranged in reverse order, and the number is the conversion result.

Decimal to hexadecimal source code

 #include <iostream> #include <string>using namespace std;string str_16= "";        string switch_10_16 (int ch) {switch (ch) {case 0:return "0";        Case 1:return "1";        Case 2:return "2";        Case 3:return "3";        Case 4:return "4";        Case 5:return "5";        Case 6:return "6";        Case 7:return "7";        Case 8:return "8";        Case 9:return "9";        Case 10:return "A";        Case 11:return "B";        Case 12:return "C";        Case 13:return "D";        Case 14:return "E";    Case 15:return "F";         }}long int change (long int num) {if (num<16) {str_16+=switch_10_16 (num);    return 0;        } else {change (NUM/16);    Str_16+=switch_10_16 (NUM%16);    }}int Main () {long str_10;    cin>>str_10;    Change (STR_10);    cout<<str_16<<endl;   return 0; } 

A brief analysis of C + + shift operation and binary conversion