learngo/08-numbers-and-strings/01-numbers/questions/03-assignment-operations.md

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2018-10-13 23:30:21 +03:00
## Which expression increases `n` by 1?
```go
var n float64
```
1. `n = +1`
2. `n = n++`
3. `n = n + 1` *CORRECT*
4. `++n`
> 1. This just assigns 1 to n.
> 2. IncDec statement can't be used as an operator.
> 4. Go doesn't support prefix incdec notation.
## Which expression decreases `n` by 1?
```go
var n int
```
1. `n = -1`
2. `n = n--`
3. `n = n - 1` *CORRECT*
4. `--n`
> 1. This just assigns -1 to n.
> 2. IncDec statement can't be used as an operator.
> 4. Go doesn't support prefix incdec notation.
## Which code below equals to `n = n + 1`?
1. `n++` *CORRECT*
2. `n = n++`
3. `++n`
4. `n = n ++ 1`
> 2. IncDec statement can't be used as an operator.
> 3. Go doesn't support prefix incdec notation.
> 4. What's that? ++?
## Which code below equals to `n = n + 1`?
1. `n = n++`
2. `n += 1` *CORRECT*
3. `++n`
4. `n = n ++ 1`
> 1. IncDec statement can't be used as an operator.
> 3. Go doesn't support prefix incdec notation.
> 4. What's that? ++?
## Which code below equals to `n -= 1`?
1. `n = n--`
2. `n += 1--`
3. `n--` *CORRECT*
4. `--n`
> 1. IncDec statement can't be used as an operator.
> 2. IncDec statement can't be used as an operator. And also, you can't use it with `1--`. The value should be addressable. You're going to learn what that means soon.
> 4. Go doesn't support prefix incdec notation.
## Which code below divides the `length` by 10?
1. `length = length // 10`
2. `length /= 10` *CORRECT*
3. `length //= 10`
> 1. What's that? `//`?
> 2. That's right. This equals to: `length = length / 10`
> 3. What's that? `//=`?
## Which code below equals to `x = x % 2`?
1. `x = x / 2`
2. `x =% x`
3. `x %= x` *CORRECT*
> 1. This is a division. You need to use the remainder operator.
> 2. Close... But, the `%` operator is on the wrong side of the assignment.
## Which function below converts a string value into a float value?
1. `fmtconv.ToFloat`
2. `conv.ParseFloat`
3. `strconv.ParseFloat` *CORRECT*
4. `strconv.ToFloat`
## Which code is correct?
If you don't remember it, this its function signature:
```go
func ParseFloat(s string, bitSize int) (float64, error)
```
1. `strconv.ParseFloat("10", 128)`
2. `strconv.ParseFloat("10", 64)` *CORRECT*
3. `strconv.ParseFloat("10", "64")`
4. `strconv.ParseFloat(10, 64)`
> 1. There are no 128-bit floating point values in Go (Actually there are, but they only belong to the compile-time).