Integer division problem

1nnocent

Integer division problem [Copy link]

 

Two integers a=3, b=2;

The integer c=a/b is obtained by dividing the two numbers (the value of c is 1, which should actually be 1.5).

If the integer c obtained by division is shifted one place to the left, will the value of c be 10 or 15?

maychang

"If the integer c obtained by division is shifted one position to the left, the value of c is 10 or 15?"

Computers use binary. Shifting left by one bit is shifting one bit in binary.

wangerxian

If we multiply the integer c obtained by division by 10, the value is 10. If we shift it left by one position, the value is 2.

lugl4313820

It depends on what type you defined ab as. If it is uint8_t c=a/b, that is, c = 1. Shift left one bit c = 2

1nnocent

wangerxian posted on 2022-6-6 19:19 [If the integer c obtained by division is multiplied by 10, it is 10. Shifting it left by one place is 2.

If two binary numbers are divided and the quotient is one decimal place, is it OK to shift the quotient right and then find the remainder by 10? How many places should we shift right?

jimtien

I don't know what you are trying to do. Binary division 3/2, assuming 4 bits, 0011/0010, the quotient is 0001, the remainder is 0001

sint27

There is a way to do it. If you want to get a decimal place, you can multiply the divisor by 10 before doing the division. This is equivalent to storing a variable that is 10 times the actual value. You can then process it accordingly when displaying or doing other calculations.

a*10/b=15

sint27

In addition, you can use the operator % to find the remainder: 3%2=1

wangerxian

1nnocent posted on 2022-6-7 09:44 If two binary numbers are divided and the quotient is one decimal place, is it okay to shift the quotient right and then find the remainder by 10? How many places should be shifted right?

Floating point types cannot be shifted left or right!

wangerxian

1nnocent posted on 2022-6-7 09:44 If two binary numbers are divided and the quotient is one decimal place, is it okay to shift the quotient right and then find the remainder by 10? How many places should be shifted right?

And the remainder can only be an integer.

freebsder

Test it out

damiaa

Serves 2

c =a/b; //==> c=1

c <<=1;// ==>c=2

If you want to get the actual data of 1.5 (which cannot be represented by integers unless double precision, floating point);

Just use floating point a, b, c all use floating point, the conclusion is 1.5

If you want to get a number like 15, you can do:

a =a*10;

c = a/b;

At this time, c is 15

If you want higher precision

You can use a*100 a*1000, but you have to consider not overflowing.

se7ens

According to other people's explanation, it should be ×2

1nnocent

jimtien posted on 2022-6-7 11:17 I don't know what you are trying to do, binary division 3/2, assuming 4 bits, 0011/0010, the quotient is 0001, the remainder is 0001

I encountered this when writing Verilog. Verilog cannot represent decimals, so I want to ask if c=3/2 directly becomes the integer 1. If so, the decimal part cannot be obtained, and another algorithm must be used.

1nnocent

damiaa posted on 2022-6-8 09:05 is 2 c =a/b; //==> c=1 c <<=1;// ==>c=2 If you want to get the actual data of 1.5...

The Verilog language is used, and there is no floating point syntax

1nnocent

freebsder posted on 2022-6-7 19:40 Test it out and see

Problem solved

1nnocent

maychang posted on 2022-6-6 18:58 "If the integer c obtained by division is shifted one bit to the left, the value of c is 10 or 15?" Computers use binary. Shifting one bit to the left is shifting binary...

"If the integer c obtained by division is shifted one position to the left, the value of c is 10 or 15?"

There is a problem with my description here. It is not a left shift, but the quotient c=3/2. The obtained c*10 cannot be 15, because the language used is Verilog, which does not have floating point syntax. But the problem has been solved now.