itly expressed his doubts whether
the go to statement should be
treated on equal syntactic footing
with the assignment statement. To
a modest extent I blame myself
for not having then drawn the
consequences of his remark.
The remark about the undesir-ability of the go to statement is far
from new. I remember having
read the explicit recommendation
to restrict the use of the go to
statement to alarm exits, but I
have not been able to trace it; presumably, it has been made by
C.A.R. Hoare. In [ 1, Sec. 3. 2. 1.]
Wirth and Hoare together make a
remark in the same direction in
motivating the case construction:
“Like the conditional, it mirrors
the dynamic structure of a program more clearly than go to
statements and switches, and it
eliminates the need for introducing a large number of labels in the
In [ 2] Guiseppe Jacopini seems
to have proved the (logical) super-fluousness of the go to statement.
The exercise to translate an arbitrary
flow diagram more or less mechanically into a jumpless one, however,
is not to be recommended. Then
the resulting flow diagram cannot
be expected to be more transparent
than the original one.
1. Wirth, Niklaus, and Hoare, C.A.R. A contribution to the development of ALGOL.
Comm. ACM 9 (June 1966), 413–432.
2. Bohn, Corrado, and Jacopini, Guiseppe. Flow
Diagrams, Turing machines and languages
with only two formation rules. Comm. ACM 9
(May 1966) 366–371.
EDSGER W. DIJKSTRA
Eindhoven, The Netherlands
Communications of the ACM
March 1968, Vol. 11, No. 3, pg 147
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