gawk 3.1.6

Version of implementation gawk of programming language AWK

A version of gawk interpreter.

Links:

Examples:

CamelCase - AWK (329):

Variable $0 stores the whole string read (as opposed to variables $1, $2 etc. which store fields of the record). split splits the string into fragments which are separated with matches to the regular expression and writes the result to the array words. After this each element of the array is converted to correct case using functions substr, toupper and tolower. 

{   text = $0;
    split(text, words, /[^a-zA-Z]+/);
    for (i=1; i<=length(words); i++) {
        res = res toupper(substr(words[i],1,1)) tolower(substr(words[i],2));
    }
    print res
}

Hello, World! - AWK (146):

The printing is done with BEGIN pattern, i.e., before processing the input. 

BEGIN { print "Hello, World!" }

Factorial - AWK (147):

This example uses iterative factorial definition. Individual statements within code block can be separated with semicolons (;) or new lines. 

BEGIN {
    f = 1
    print "0! = " f
    for (i=1; i<17; i++) {
        f *= i
        print i "! = " f
    }
}

Fibonacci numbers - AWK (148):

This example uses iterative definition of Fibonacci numbers. fib is an associative array, and pr is a string. 

BEGIN {
    fib[1] = 1
    fib[2] = 1
    for (i=3; i<17; i++)
        fib[i] = fib[i-1]+fib[i-2]
    pr = ""
    for (i=1; i<17; i++)
        pr = pr fib[i] ", "
    print pr "..." 
}

Quadratic equation - AWK (203):

{   A = $1
    B = $2
    C = $3
    if (A == 0) 
        print "Not a quadratic equation"
    else
    {   D = B*B-4*A*C
        if (D == 0)
            print "x = " (-B/2/A)
        else if (D > 0)
        {   print "x1 = " ((-B+sqrt(D))/2/A)
            print "x2 = " ((-B-sqrt(D))/2/A)
        }
        else
        {   print "x1 = (" (-B/2/A) "," (sqrt(-D)/2/A) ")"
            print "x2 = (" (-B/2/A) "," (-sqrt(-D)/2/A) ")"
        }
    }
}

CamelCase - AWK (330):

mawk provides no function length to get the size of the array, neither it can be used in Jawk — an attempt results in “Cannot evaluate an unindexed array.” runtime error.

Instead we can use the fact that function split returns the number of string fragments it extracted from the string. Otherwise this example is identical to this one. 

{   text = $0;
    N = split(text, words, /[^a-zA-Z]+/);
    for (i=1; i<=N; i++) {
        res = res toupper(substr(words[i],1,1)) tolower(substr(words[i],2));
    }
    print res
}