: =, >, <, >=, <=, <>. : , ASCII ASCII - . : , .
, , .
| : | ||
| "aa"="aa" | "aa"¹" aa" | |
| "10"="10" | "10"¹"01 | |
| ""="" | ""¹"" | "" "" |
| "QB" = "Q" + "B" | "norma"¹"" |
IF: INPUT A$: INPUT B$ IF A$ - $ THEN PRINT "" ELSE PRINT "He "
, , ASCII- , . , ASCII- , , .
. . , , . , , .
| : | |
| "ww2" > "ww" | , |
| "ww2" > "wwO" | ASII- 2 (50), ASII- 0 (48) |
| "f > "p" | ASII- f (102) F (70) |
| "A" > "A" | ASII- (128) ASII- (65) |
| "file.dat" > "file.bas" | ASII- d b |
| "21" > "2"+"00" | ASII- 1 , ASII- 0 |
, . , , , , .
| 1. | LEN | |
| 2. | LEFT$ | () . |
| 3. | RIGHT$ | LEFT$, () . |
| 4. | MID$ | n , k-. |
| 5. | MID$ | n , k-, . |
| 6. | INSTR | , |
| 7. | LTRIM$ RTRIM$ | () () , . |
| 8. | ASC | ASCII, . |
| 9. | CHR$ | , ASCII. |
LEN
|
|
|
.
LN (_)
_ , . , , , .
1. .
A$ =
X = LEN (A$): PRINT X
PRINT LEN(A$ + BASIC)
1:
. LEN $. X , . LEN $ .
LEFT$
. .
LF$ (_. N)
_ , , ;
N . N , .
2. LEFT$.
$ = "Microsoft"
$ = LEFT$(A$. 5): PRINT B$ '1
PRINT LEFT$(A$, LEN(A$) - 4) '2
PRINT LEFT$("Computer". 4) + "IBM" '3
:
Micro
Micro
CompIBM
. . LEFT$ 5 $. '2 . LEN(A$) - 4 $, . '3 , , .
RIGHT$
LEFT$, () .
RIGHT$ (_. N)
LEFT$, .
MID$
n , k-.
|
|
|
ID$ (_. k [. n])
_ , , k , . k , , ID$ (""). k , Illegal function call ( ). n , . n n < k, , k- . n = 0 , .
k n , . .
3. , ID$.
$ = ""
M$ = MID$(A$, 3, 6)
PRINT M$
PRINT MID$(A$, 3)
:
. MID$ 6 , , $ $. MID$ $, , .
MID$
MID$ n , k-, . . n , k-, n , .
4:
$ = "123456"
ID$($, 3, 2) = "abc"
PRINT A$
:
12b56
$, , abc.
:
ID$ (._.., k[,n]) = _
k _, . k , , Illegal function call ( ), n . k + n , , k-, _. _ - , n . n, , .
5. MID$.
A$ = "123456": MID$(A$, 1, 3) = "abc" '1
PRINT A$
A$ = "123456": MID$(A$, 5, 3) = "abc" '2
PRINT A$
A$ = "123456": MID$(A$, 2) = "abcdefghijk" '3
PRINT A$
A$ = "123456": MID$(A$, 4!, 2) = MID$("abc", 2, 1) '4
PRINT A$
:
abc456
1234ab
1abcde
123b56
, '1 , , abc. '2 , , 6 , . '3 MIDS ( ). . 6 , $ . '4 MID$. abc, $. , , , $ , .
INSTR
, . , , .
|
|
|
INSTR ([k], __1. __2)
__2 __1. k , . , .
