line feed normally printed between arguments. ALIGNED(1,6) controls the format of the output with 1 digit before and 6 after the decimal point. ALGOL 68 The following code samples are ALGOL 68 versions of the above ALGOL 60 code samples. ALGOL 68 implementations used ALGOL 60's approaches to stropping. In ALGOL 68's case tokens with the bold typeface are reserved words, types (modes) or operators. proc abs max = ([,]real a, ref real y, ref int i, k)real: comment The absolute greatest element of the matrix a, of size ⌈a by 2⌈a is transferred to y, and the subscripts of this element to i and k; comment begin real y := 0; i := ⌊a; k := 2⌊a; for p from ⌊a to ⌈a do for q from 2⌊a to 2⌈a do if abs a[p, q] > y then y := abs a[p, q]; i := p; k := q fi od od; y end # abs max # Note: lower (⌊) and upper (⌈) bounds of an array, and array slicing, are directly available to the programmer. floating point algol68 test: ( real a,b,c,d; # printf – sends output to the file stand out. # # printf($p$); – selects a new page # printf(($pg$,"Enter d:")); read(d); for step from 0 while a:=step*d; a <= 2*pi do printf($l$); # $l$ - selects a new line. # b := sin(a); c := cos(a); printf(($z-d.6d$,a,b,c)) # formats output with 1 digit before and 6 after the decimal point. # od ) Timeline: Hello world The variations and lack of portability of the programs from one implementation to another is easily demonstrated by the classic hello world program. ALGOL 58 (IAL) ALGOL 58 had no I/O facilities. ALGOL 60 family Since ALGOL 60 had no I/O facilities, there is no portable hello world program in ALGOL. The next three examples are in Burroughs Extended Algol. The first two direct output at the interactive terminal they are run on. The first uses a character array, similar to C. The language allows the array identifier to be used as a pointer to the array, and hence in a REPLACE statement. A simpler program using an inline format: An even simpler program using the Display statement. Note that its output would end up at the system console ('SPO'): An alternative example, using Elliott Algol I/O is as follows. Elliott Algol used different characters for "open-string-quote" and