CS计算机代考程序代写 import “io”
import “io”
/*
devctl(DC_TAPE_LOAD, unit#, “filename”, ‘R’ or ‘W’)
devctl(DC_TAPE_READ, unit#, buffer)
devctl(DC_TAPE_WRITE, unit#, buffer, blocksizeinbytes)
devctl(DC_TAPE_UNLOAD, unit#)
all return codes pos or zero = success
negative is error message index
for read, the result is size of block
*/
let buffer = vec(128);
let pos = 0;
let wopen(fname) be
{ let r = devctl(DC_TAPE_LOAD, 1, fname, ‘W’);
if r < 0 then
{ out("code %d from tape load
", r);
finish }
pos := 0 }
let wclose() be
{ let r;
if pos /= 0 then
{ let r = devctl(DC_TAPE_WRITE, 1, buffer, pos);
if r < 0 then
{ out("code %d from tape write
", r);
finish } }
r := devctl(DC_TAPE_UNLOAD, 1);
if r < 0 then
{ out("code %d from tape unload
", r);
finish } }
let wchar(c) be
{ if pos = 512 then
{ let r = devctl(DC_TAPE_WRITE, 1, buffer, 512);
if r < 0 then
{ out("code %d from tape write
", r);
finish }
pos := 0 }
byte pos of buffer := c;
pos +:= 1 }
let wstring(s) be
{ let i = 0;
while true do
{ let c = byte i of s;
if c = 0 then break;
wchar(c);
i +:= 1 } }
let wnum(n) be
{ if n > 9 then
wnum(n / 10);
wchar(‘0’ + n rem 10) }
let start() be
{ wopen(“table.txt”);
for c = 0 to 100 do
{ let f = c * 9 / 5 + 32;
wnum(c);
wstring(” centigrade is “);
wnum(f);
wstring(” fahrenheit
”) }
wclose() }
