📄 bc.1
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2633(implied)S2969(")S10 B3010(return)S3320(\(0\))S10 R3438(")S3508(at)S3610(the)S3762(end)S3936(of)S4049(every)S4302(function.)S4716(This)S4924(allows)S5216(a)S5352 V1080(function)S1440(to)S1543(terminate)S1949(and)S2119(return)S2385(0)S(without)307 2460 A2792(an)S2912(explicit)S3239(return)S3505(statement.)S5520 V1080(Functions)S1506(also)S1698(change)S2013(the)S2166(usage)S2425(of)S2539(the)S2692(variable)S10 B3047(ibase)S10 R3265(.)S3345(All)S3504(constants)S3908(in)S4017(the)S4171(function)S(body)200 4537 A(will)157 4768 A4956(be)S5082(con-)S5640 V1080(verted)S1358(using)S1601(the)S1750(value)S1994(of)S10 B2104(ibase)S10 R2348(at)S2447(the)S2596(time)S2801(of)S2911(the)S3060(function)S3421(call.)S3642(Changes)S4013(of)S10 B4122(ibase)S10 R(will)157 4365 A4547(be)S(ignored)307 4667 A4999(during)S5760 V1080(the)S1234(execution)S1656(of)S1771(the)S1925(function)S2291(except)S2585(for)S2734(the)S2888(standard)S3260(function)S10 B3626(read)S10 R3822(,)S3878(which)S(will)157 4155 A4343(always)S4654(use)S4820(the)S4975(current)S5880 V1080(value)S1323(of)S10 B1432(ibase)S10 R1675(for)S(conversion)441 1818 A2284(of)S2393(numbers.)S6048 V870(M)S872(MA)S963(AT)S1038(TH)S1102(H)S1218(L)S1220(LI)S1284(IB)S1320(BR)S1389(RA)S1458(AR)S1533(RY)S1602(Y)S6168 V1080(If)S10 B1179(bc)S10 R1311(is)S(invoked)323 1409 A1763(with)S1973(the)S10 B2127(-l)S10 R2220(option,)S2532(a)S2608(math)S2840(library)S3140(is)S3238(preloaded)S3666(and)S3843(the)S3998(default)S4310(scale)S4544(is)S4643(set)S4787(to)S4897(20.)S5104(The)S6288 V1080(math)S1320(functions)S(will)157 1732 A1927(calculate)S2324(their)S2547(results)S2848(to)S2964(the)S3125(scale)S3365(set)S3515(at)S3626(the)S3787(time)S4004(of)S4126(their)S4349(call.)S4558(The)S4753(math)S4992(library)S6408 V1080(de\256nes)S1390(the)S1538(following)S1954(functions:)S6576 V1080(s)S1144(\()S10 I1178(x)S10 R1223(\))S1440(The)S1622(sine)S1809(of)S1918(x)S1993(in)S2096(radians.)S6744 V1080(c)S1150(\()S10 I1184(x)S10 R1229(\))S1440(The)S1622(cosine)S1904(of)S2013(x)S2088(in)S2191(radians.)S6912 V1080(a)S1150(\()S10 I1184(x)S10 R1229(\))S1440(The)S1622(arctangent)S2067(of)S2176(x.)S7080 V1080(l)S1133(\()S10 I1167(x)S10 R1212(\))S1440(The)S1622(natural)S1927(logarithm)S2343(of)S2452(x.)S7248 V1080(e)S1150(\()S10 I1184(x)S10 R1229(\))S1440(The)S(exponential)469 1622 A2116(function)S2476(of)S2585(raising)S2884(e)S2954(to)S3057(the)S3205(value)S3448(x.)S7903 V720(September)S1176(13,)S(1996)200 1326 A2936(\()S2978(.)S3011(\))S4990(Page)S5211(6)S8143 VEP%%Page: 7 7BP/slant 0 def/height 0 def480 V10 R720(bc)S823(\()S865(1)S923(\))S2696(Eighth)S(Edition)296 2989 A5024(bc)S5127(\()S5169(1)S5227(\))S960 V1080(j)S1133(\()S10 I1167(n,x)S10 R1287(\))S1440(The)S1622(bessel)S1893(function)S2253(of)S2362(integer)S2667(order)S2905(n)S2980(of)S3089(x.)S1128 V870(E)S872(EX)S936(XA)S1011(AM)S1086(MP)S1177(PL)S1235(LE)S1299(ES)S1363(S)S1248 V1080(In)S1189(/bin/sh,)S1537(the)S1685(following)S(will)157 2101 A2283(assign)S2559(the)S2707(value)S2950(of)S3059("pi")S3244(to)S3347(the)S3495(shell)S3710(variable)S10 B4060(pi)S10 R4144(.)S1488 V10 B1440(pi=$\(echo)S1886("scale=10;)S(4*a\(1\)")324 2365 A2714(|)S2761(bc)S2887(-l\))S1776 V10 R1080(The)S1272(following)S1698(is)S1800(the)S(de\256nition)385 1958 A2378(of)S2497(the)S(exponential)469 2655 A3159(function)S3529(used)S3748(in)S3861(the)S4019(math)S4255(library.)S4609(This)S4823(function)S5194(is)S1896 V(written)286 1080 A1391(in)S1494(POSIX)S10 B1811(bc)S10 R1912(.)S2136 V10 B1440(scale)S1672(=)S1754(20)S2376 V1440(/*)S1543(Uses)S1764(the)S1924(fact)S2112(that)S2311(e\303x)S2465(=)S(\(e\303\(x/2\)\)\3032)427 2547 A2496 V1515(When)S1797(x)S1872(is)S1964(small)S2218(enough,)S2581(we)S2724(use)S2889(the)S3049(series:)S2616 V1565(e\303x)S1719(=)S1801(1)S1876(+)S1958(x)S2033(+)S2115(x\3032/2!)S2386(+)S2468(x\3033/3!)S2739(+)S(...)75 2821 A2736 V1440(*/)S2976 V1440(de\256ne)S1723(e\(x\))S1911({)S3096 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A2386(v)S2461(=)S(v*v;)184 2543 A6096 V1590(scale)S1822(=)S1904(z)S6216 V1590(if)S1677(\(m\))S1854(return)S2160(\(1/v\);)S6336 V1590(return)S1896(\(v/1\);)S6456 V1540(})S6576 V1540(v)S1615(+=)S1754(e)S6696 V1490(})S6816 V1440(})S7104 V10 R1080(The)S1262(following)S1678(is)S1770(code)S1985(that)S2161(uses)S2359(the)S2507(extended)S2895(features)S3240(of)S10 B3350(bc)S10 R3477(to)S3581(implement)S4037(a)S4108(simple)S4402(program)S4769(for)S4913(calculat-)S7224 V1080(ing)S(checkbook)435 1239 A1705(balances.)S2133(This)S2343(program)S2715(is)S2813(best)S3006(kept)S3210(in)S3319(a)S3395(\256le)S3555(so)S3675(that)S3857(it)S3944(can)S4114(be)S4239(used)S4453(many)S4706(times)S(without)307 4954 A7344 V1080(having)S1378(to)S1481(retype)S1758(it)S1839(at)S1937(every)S2186(use.)S7903 V720(Page)S941(7)S2936(\()S2978(.)S3011(\))S4455(September)S4911(13,)S(1996)200 5061 A8143 VEP%%Page: 8 8BP/slant 0 def/height 0 def480 V10 R720(bc)S823(\()S865(1)S923(\))S2696(Eighth)S(Edition)296 2989 A5024(bc)S5127(\()S5169(1)S5227(\))S960 V10 B1440(scale=2)S1080 V1440(print)S1684("\\nCheck)S2124(book)S2361(program!\\n")S1200 V1440(print)S1684(")S1790(Remember,)S2317(deposits)S2689(are)S2854(negative)S3237(transactions.\\n")S1320 V1440(print)S1684(")S1790(Exit)S1994(by)S2125(a)S2200(0)S2275(transaction.\\n\\n")S1560 V1440(print)S1684("Initial)S2028(balance?)S2433(";)S2548(bal)S2707(=)S2789(read\(\))S1680 V1440(bal)S1599(/=)S1709(1)S1800 V1440(print)S1684("\\n")S1920 V1440(while)S1695(\(1\))S1838({)S2040 V("current)382 1490 A1897(balance)S2252(=)S2334(";)S2449(bal)S2160 V1490("transaction?)S2108(";)S2223(trans)S2472(=)S2554(read\(\))S2280 V1490(if)S1577(\(trans)S1860(==)S1999(0\))S2108(break;)S2400 V1490(bal)S1649(-=)S1765(trans)S2520 V1490(bal)S1649(/=)S1759(1)S2640 V1440(})S2760 V1440(quit)S3048 V10 R1080(The)S1262(following)S1678(is)S1770(the)S(de\256nition)385 1918 A2328(of)S2437(the)S2585(recursive)S2980(factorial)S3342(function.)S3288 V10 B1440(de\256ne)S1723(f)S1782(\(x\))S1925({)S3408 V1490(if)S1577(\(x)S1686(<=)S1825(1\))S1934(return)S2240(\(1\);)S3528 V1490(return)S(\(f\(x-1\))270 1796 A2091(*)S2166(x\);)S3648 V1440(})S3936 V10 R870(D)S872(DI)S947(IF)S983(FF)S1041(FE)S1099(ER)S1163(RE)S1232(EN)S1296(NC)S1371(CE)S1440(ES)S1504(S)S4056 V1080(This)S1293(version)S1623(of)S10 B1741(bc)S10 R1876(was)S2067(implemented)S2626(from)S2856(the)S3013(POSIX)S(P1003.2/D11)532 3339 A3905(draft)S4131(and)S4311(contains)S4681(several)S5002(differ-)S4176 V1080(ences)S1333(and)S1507(extensions)S1960(relative)S2292(to)S2399(the)S2551(draft)S2771(and)S(traditional)414 2945 A3388(implementations.)S4137(It)S4228(is)S4323(not)S4479(implemented)S5032(in)S5138(the)S4296 V(traditional)414 1080 A1522(way)S1718(using)S10 I1963(dc\(1\).)S10 R2229(This)S2436(version)S2761(is)S2857(a)S2931(single)S3200(process)S3531(which)S3806(parses)S4087(and)S4261(runs)S4463(a)S4537(byte)S4739(code)S4958(transla-)S4416 V1080(tion)S1263(of)S1374(the)S1524(program.)S1941(There)S2203(is)S2296(an)S("undocumented")673 2417 A3116(option)S3398(\(-c\))S3571(that)S3748(causes)S4037(the)S4186(program)S4553(to)S4657(output)S4939(the)S5088(byte)S4536 V1080(code)S1309(to)S1426(the)S1588(standard)S1968(output)S2263(instead)S2587(of)S(running)312 2710 A3061(it.)S3206(It)S3307(was)S3503(mainly)S3821(used)S4045(for)S(debugging)423 4203 A4666(the)S4829(parser)S5116(and)S4656 V1080(preparing)S1491(the)S1639(math)S1865(library.)S4824 V1080(A)S1182(major)S1446(source)S1738(of)S1851(differences)S2329(is)S2425(extensions,)S2903(where)S3179(a)S3253(feature)S3563(is)S3659(extended)S4052(to)S4160(add)S4335(more)S(functionality)514 4572 A5116(and)S4944 V(additions,)393 1080 A1498(where)S1770(new)S1963(features)S2308(are)S2457(added.)S2747(The)S2929(following)S3345(is)S3437(the)S3585(list)S3733(of)S3842(differences)S4316(and)S4486(extensions.)S5112 V(LANG)281 1080 A1630(This)S1848(version)S2183(does)S2406(not)S2573(conform)S2953(to)S3070(the)S3232(POSIX)S3563(standard)S3943(in)S4060(the)S4223(processing)S4693(of)S4817(the)S(LANG)281 4980 A5232 V1630(environment)S2163(variable)S2513(and)S2683(all)S2809(environment)S3342(variables)S3731(starting)S4058(with)S4262(LC_.)S5400 V1080(names)S(Traditional)448 1630 A2115(and)S2297(POSIX)S10 B2626(bc)S10 R2764(have)S2992(single)S3270(letter)S3516(names)S3811(for)S3967(functions,)S4404(variables)S4806(and)S4989(arrays.)S5520 V1630(They)S1863(have)S2079(been)S2295(extended)S2684(to)S2788(be)S(multi-character)617 2908 A3550(names)S3832(that)S4008(start)S4207(with)S4411(a)S4481(letter)S4714(and)S4884(may)S5082(con-)S5640 V1630(tain)S1806(letters,)S2103(numbers)S2474(and)S2644(the)S(underscore)442 2792 A3259(character.)S5808 V1080(Strings)S1630(Strings)S1950(are)S2110(not)S2274(allowed)S2629(to)S2743(contain)S3075(NUL)S3319(characters.)S3815(POSIX)S4143(says)S4352(all)S4489(characters)S4935(must)S5166(be)S5928 V1630(included)S2001(in)S2104(strings.)S6096 V1080(last)S1630(POSIX)S10 B1953(bc)S10 R2085(does)S2300(not)S2459(have)S2680(a)S10 B2756(last)S10 R2939(variable.)S3346(Some)S3607(implementations)S4309(of)S10 B4425(bc)S10 R4558(use)S4724(the)S4879(period)S5168(\(.\))S6216 V1630(in)S1733(a)S1803(similar)S2108(way.)S6384 V1080(comparisons)S1630(POSIX)S10 B1967(bc)S10 R2113(allows)S2421(comparisons)S2974(only)S3197(in)S3320(the)S3488(if)S3595(statement,)S4051(the)S4220(while)S4490(statement,)S4947(and)S5138(the)S6504 V(second)279 1630 A1940(expression)S2401(of)S2516(the)S2670(for)S2819(statement.)S3286(Also,)S3532(only)S3741(one)S3916(relational)S4327(operation)S4737(is)S4834(allowed)S5183(in)S6624 V(each)185 1630 A1840(of)S1949(those)S2186(statements.)S6792 V1080(if)S1167(statement,)S1603(else)S1785(clause)S6912 V1630(POSIX)S10 B1947(bc)S10 R2073(does)S2282(not)S2435(have)S2650(an)S2770(else)S2952(clause.)S7080 V1080(for)S1223(statement)S7200 V1630(POSIX)S10 B1947(bc)S10 R2073(requires)S2423(all)S2549(expressions)S3043(to)S3146(be)S3266(present)S3582(in)S3685(the)S3833(for)S3976(statement.)S7368 V1080(&&,)S1286(||,)S1376(!)S1630(POSIX)S10 B1947(bc)S10 R2073(does)S2282(not)S2435(have)S2650(the)S2798(logical)S3097(operators.)S7903 V720(September)S1176(13,)S(1996)200 1326 A2936(\()S2978(.)S3011(\))S4990(Page)S5211(8)S8143 VEP⌨️ 快捷键说明
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