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Unformatted text preview: n that achieved by the earlier Ariane 4 rocket. In the design of the Ariane 4 software, they had carefully analyzed the numeric values and determined that the horizontal velocity would never overﬂow a 16-bit number. Unfortunately, they simply reused this part of the software in the Ariane 5 without checking the assumptions on which it had been based. End Aside. 2.5. SUMMARY
Practice Problem 2.28:
Assume variables x, f, and d are of type int, float, and double, respectively. Their values are arbitrary, except that neither f nor d equals ·½, ½, or Æ Æ . For each of the following C expressions, either argue that it will always be true (i.e., evaluate to 1) or give a value for the variables such that it is not true (i.e., evaluates to 0). A. x == (int)(float) x B. x == (int)(double) x C. f == (float)(double) f D. d == (float) d E. f == -(-f) F. 2/3 == 2/3.0 G. (d >= 0.0) || ((d*2) < 0.0) H. (d+f)-d == f 79 2.5 Summary
Computers encode information as bits, generally organized as sequences of bytes. Different encodings are used for representing integers, real numbers, and character strings. Different models of comput...
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