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1.1 root 1:
2:
3: bc Command bc
4:
5:
6:
7:
8: Interactive calculator with arbitrary precision
9:
10: bbcc [ -ll ] [ _f_i_l_e ... ]
11:
12: bc is a language that performs calculations on numbers with an
13: arbitrary number of digits. bc is most commonly used as an in-
14: teractive calculator, where the user types arithmetic expressions
15: in a syntax reminiscent of C. If bc is invoked with no file ar-
16: guments on its command line, it reads the standard input. For
17: example:
18:
19:
20: _I_n_p_u_t _O_u_t_p_u_t
21: bc
22: (1000+23)*42 42966
23: k = 2^10
24: 16 * k 16384
25: 2 ^ 100 1267650600228229401496703205376
26:
27:
28: bc may also be invoked with one or more file arguments. After bc
29: reads each file, it reads the standard input. This provides a
30: convenient way to access programs in files. A library of mathe-
31: matical functions is available, obtained by using the -l option.
32:
33: The following summarizes briefly the facilities provided by bc.
34: More information is available in the tutorial to bbcc that is in-
35: cluded with this manual.
36:
37: Comments are enclosed between the delimiters `/*' and `*/'.
38: Names of variables or functions must begin with a lower-case let-
39: ter, and may have any number of subsequent letters or digits.
40: Names may not begin with an upper-case letter because numbers
41: with a base greater than ten may need need upper-case letters for
42: their notation. The three built-in variables obase, ibase, and
43: scale represent the number base for printing numbers (default,
44: ten), the number base for reading numbers (default, ten), and the
45: number of digits after the decimal (radix) point (default, zero),
46: respectively. Variables may be simple variables or arrays, and
47: need not be pre-declared, with the exception of variables inter-
48: nal to functions. Some examples of variables and array elements
49: are x25, array[10], and number.
50:
51: Numbers are any string of digits, and may have one decimal point.
52: Digits are taken from the ordinary digits (0-9) and then the up-
53: per-case letters (A-F), in that order.
54:
55: Certain names are reserved for use as key words. The key words
56: recognized by bc include the following:
57:
58: iiff, ffoorr, ddoo, wwhhiillee
59: Test conditions and define loops, with syntax identical to C
60:
61:
62:
63:
64: COHERENT Lexicon Page 1
65:
66:
67:
68:
69: bc Command bc
70:
71:
72:
73: bbrreeaakk, ccoonnttiinnuuee
74: Alter control flow within for and while loops.
75:
76: qquuiitt Tell bc to exit immediately
77:
78: ddeeffiinnee _f_u_n_c_t_i_o_n (_a_r_g, ..., _a_r_g)
79: Define a bc function by a compound statement, as in C.
80:
81: aauuttoo _v_a_r, ..., _v_a_r
82: Define variables that are local to a function, rather than
83: having global scope.
84:
85: rreettuurrnn (_v_a_l_u_e)
86: Return a value from a function.
87:
88: ssccaallee (_v_a_l_u_e)
89: Return the number of digits to the right of the decimal
90: point in value.
91:
92: ssqqrrtt (_v_a_l_u_e)
93: Return the square root of value
94:
95: lleennggtthh (_v_a_l_u_e)
96: Return the number of decimal digits in value.
97:
98: The following operators are recognized:
99:
100:
101: + -* / % ^ ++
102: -- =+= -= *= /= %=
103: ^= ==!= < <= > >=
104:
105:
106: These operators are similar to those in C, with the exception of
107: ^ and ^=, which are exponentiation operators. Expressions can be
108: grouped with parentheses. Statements are separated with semi-
109: colons or newlines, and may be made into compound statements with
110: braces. bc prints the value of any statement that is an expres-
111: sion but is not an assignment.
112:
113: As in the editor ed, an `!' at the beginning of a line causes
114: that line to be sent as a command to the COHERENT shell sh.
115:
116: The built-in mathematics library contains the following functions
117: and variables:
118:
119:
120: aattaann(_z) Arctangent of _z
121: ccooss(_z) Cosine of _z
122: eexxpp(_z) Exponential function of _z
123: jj(_n,_z) _nth order Bessel function of _z
124: llnn(_z) Natural logarithm of _z
125: ppii Value of pi to 100 digits
126: ssiinn(_z) Sine of _z
127:
128:
129:
130: COHERENT Lexicon Page 2
131:
132:
133:
134:
135: bc Command bc
136:
137:
138:
139:
140: ***** Examples *****
141:
142: The first example calculates the factorial of its positive in-
143: teger argument by recursion.
144:
145:
146: /*
147: * Factorial function implemented by recursion.
148: */
149: define fact(n) {
150: if (n <= 1) return (n);
151: return (n * fact(n-1));
152: }
153:
154:
155: The second example also calculates the factorial of its positive
156: integer argument, this time by iteration.
157:
158:
159: /*
160: * Factorial function implemented by iteration.
161: */
162: define fact(n) {
163: auto result;
164:
165: result = 1;
166: for (i=1; i<=n; i++) result *= i;
167: return (result);
168: }
169:
170:
171: ***** Files *****
172:
173: /uussrr/lliibb/lliibb.bb -- Source code for the library
174:
175: ***** See Also *****
176:
177: commands, conv, dc, multi-precision arithmetic
178: _b_c _D_e_s_k _C_a_l_c_u_l_a_t_o_r _L_a_n_g_u_a_g_e, tutorial
179:
180: ***** Notes *****
181:
182: Line numbers do not accompany error messages in source files.
183:
184:
185:
186:
187:
188:
189:
190:
191:
192:
193:
194:
195:
196: COHERENT Lexicon Page 3
197:
198:
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