PROGRAM MACHIN C C This code calculates the smallest number U such that (1.0+U) .GT. 1.0. C U is computed approximately as the half power of 1./2. This code is from C page 209 of Shampine and Gordon (1975), "The Solution to Ordinary C Differential Equations". C HALFU = 0.5 50 TEMP1 = 1.0 + HALFU IF (TEMP1 .LE. 1.0) GO TO 100 HALFU = 0.5*HALFU GO TO 50 100 U = 2.0*HALFU WRITE(*, 200) U, 2.*U, 4.0*U 200 FORMAT(/' Machine Dependent Roundoff Error:',//' U = ',F11.8, 1 ', TWOU = ',F11.8,', FOURU = ',F11.8,'.'//) STOP END