Read from Terminal and Files¶
var = xred(promptstring, default, min, max)
Xred()reads a value from the standard input after printing promptstring on the console. The value read must be in the range min <= val <= max and the user will be prompted to enter another number if the value is not in that range. If the user types the Return key, the default value is used (if it is in the valid range).
Getstr()reads a string up to and including the next newline from the file opened with the
ropen()command (or the currently executing file or the standard input) and places it in its string variable argument. With a second arg equal to 1, getstr reads a single word starting at the next non-whitespace character up to but not including the following whitespace (similar to fscan).
index = sred(prompt, defaultchar, charlist)
sred()reads a character typed on the standard input after printing the first argument followed by the default character. The user is required to enter one of the characters in the character list (or return if the default happens to be one of these characters). The function returns the index in the character list of the character typed. The index of the first character is 0. The character accepted becomes the next default when this statement is executed again. This function was contributed by Stewart Jaslove.
i = sred("Shall we?", "y", "ny") if (i == 0) print "No" else print "yes"
var = fscan()
fscan()reads the next number from the file opened with the
ropen()command. If no file is opened the number is read from the currently executing file. If no file is being executed the number is read from the standard input. A number is scanned as long as it begins with a digit, decimal point, or sign. There can be more than one number per line but they must be set apart from each other by spaces or tabs. Strings that can’t be scanned into numbers are skipped.
Suppose in response to the HOC command:
print fscan(), fscan()the user types:
this is a number 1.3e4 this is not45 this is 25Then HOC will print:
while(1) print fscan() notice that when no file is open, fscan scans the remainder of the hoc file following only scans the numbers from 10 to 170 10 n 20 n 30 na 40 nan 50 nano 60 nanotube 70 ni 80 nai 90 Nan NaN i 100 in 110 inf 120 infi 130 ib 140 inc 150 infinity 160 170 Inf INF following scans the numbers 1 2 3 4 5 6 7 8 9 10 - + does not scan 1.1 -1.2 1.3e-4 1.4e+4 -1.5e5 -1.6e-1 1+2+3 scans just the "1" 4xxx5 scans just the "4" 1,2,3 scans just the "1" 3, 4, 5 scans the three numbers now there will be an EOF error
getstr()returns to the HOC interpreter with a run-time error on EOF.