Terminal control/Restricted width positional input/No wrapping: Difference between revisions
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This uses _getch() rather than _getwch() as only ASCII is supported. |
This uses _getch() rather than _getwch() as only ASCII is supported. |
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<lang go> |
<lang go>package main |
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package main |
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/* |
/* |
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setCursor(coord) |
setCursor(coord) |
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fmt.Printf("You entered '%s'\n", s) |
fmt.Printf("You entered '%s'\n", s) |
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} |
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=={{header|Kotlin}}== |
=={{header|Kotlin}}== |
Revision as of 12:07, 7 November 2018
Create a routine to obtain data entry using a specific place on the terminal screen. Data entry fields should be restricted to a specific length, and it should not be possible for the cursor to move beyond the input length.
The routine should accept parameters for row number, column number and input length, and should obtain a string value entered by the user.
For the purpose of this task, obtain input from the user, showing data entry at row 3, column 5, with input width restricted to a maximum of 8 characters.
Note: In this task input wrapping is not allowed. (See Terminal control/Restricted width positional input/With wrapping) for input wrapping variant.
For a similar task using a graphical user interface, see Graphical User Interface/Restricted width positional input/No wrapping.
Go
This uses _getch() rather than _getwch() as only ASCII is supported.
<lang go>package main
/*
- include <windows.h>
- include <conio.h>
- /
import "C" import (
"fmt" "os" "os/exec"
)
var conOut = C.GetStdHandle(C.STD_OUTPUT_HANDLE)
func setCursor(p C.COORD) {
C.SetConsoleCursorPosition(conOut, p)
}
func cls() {
cmd := exec.Command("cmd", "/c", "cls") cmd.Stdout = os.Stdout cmd.Run()
}
func getInput(row, col, width int) string {
if row < 0 || row > 20 || col < 0 || width < 1 || width > 78 || col > (79 - width) { panic("Invalid parameter(s) to getInput. Terminating program") } coord := C.COORD{C.short(col), C.short(row)} setCursor(coord) var sb []byte full := false loop: for { ch := C._getch() // gets next character, no echo switch c := byte(ch); c { case 3, 13: break loop // break on Ctrl-C or enter key case 8: if len(sb) > 0 { // mimic backspace
fmt.Print("\b \b")
sb = sb[:len(sb) - 1] } case 0, 224: C._getch() // consume extra character default: if c >= 32 && c <= 126 && !full { C._putch(ch) // echo ascii character, ignore others sb = append(sb, c) } } full = len(sb) == width // can't exceed width } return string(sb)
}
func main() {
cls() // clear the console s := getInput(2, 4, 8) // Windows console row/col numbering starts at 0 coord := C.COORD{0, 22} setCursor(coord) fmt.Printf("You entered '%s'\n", s)
}</lang>
Kotlin
This assumes an 80 x 25 Windows console and uses the Win32 function _getwch() to get character input without (immediately) echoing it to the console. Only ASCII characters in the range 32 to 126 are then printed if the maximum width would not be exceeded.
Apart from these, only the backspace key (8), return key (13) and Ctrl-C (3) are handled, all other keys being ignored. Some keys (such as the function and arrow keys) return a two character sequence starting with either 0 or 224 and so, after the first character is trapped, the second character needs to be removed from the buffer.
It would also be possible to allow for printable Unicode characters (>= 160) to be entered by adding an extra clause to the 'when' statement. However, for this to work properly, you will need to be using a suitable code page (65001, say) and a suitable font (Lucida Console, say). <lang scala>// Kotlin Native v0.5
import kotlinx.cinterop.* import platform.windows.* import platform.posix.*
val ascii = 32..126 val conOut = GetStdHandle(STD_OUTPUT_HANDLE)!!
fun setCursor(p: COORD) = SetConsoleCursorPosition(conOut, p.readValue())
fun getInput(row: Short, col: Short, width: Int): String {
require(row in 0..20 && col in 0..(79 - width) && width in 1..78) { "Invalid parameter(s)" } memScoped { val coord = alloc<COORD>().apply { X = col; Y = row } setCursor(coord) } val sb = StringBuilder(width) var full = false loop@ while (true) { val ch = _getwch() // gets next character, no echo when (ch.toInt()) { 3, 13 -> break@loop // break on Ctrl-C or enter key 8 -> if (sb.length > 0) { print("\b \b"); sb.length-- } // mimic backspace 0, 224 -> _getwch() // consume extra character in ascii -> if (!full) { _putwch(ch); sb.append(ch.toChar()) } // echo ascii character else -> {} // igore other characters } full = sb.length == width // can't exceed width } return sb.toString()
}
fun main(args: Array<String>) {
system("cls") // clear the console val s = getInput(2, 4, 8) // Windows console row/col numbering starts at 0 memScoped { val coord = alloc<COORD>().apply { X = 0 ; Y = 22 } setCursor(coord) } println("You entered '$s'")
}</lang>
Phix
<lang Phix>function getInput(integer row, col, width)
position(row,col) string s = "" while 1 do integer ch = wait_key() if ch='\r' then exit end if if ch='\b' then if length(s)>0 then puts(1,"\b \b") s = s[1..$-1] end if elsif ch>=' ' and ch<='~' then if length(s)<=width then puts(1,ch) s &= ch end if end if end while return s
end function
clear_screen() -- clear the console string s = getInput(3, 5, 8) position(23,1) printf(1,"You entered '%s'\n",{s})</lang>