1BC(1) General Commands Manual BC(1)
2
6 bc - arbitrary-precision arithmetic language
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9 bc [ -c ] [ -l ] [ file ... ]
10
12 Bc is an interactive processor for a language which resembles C but
13 provides unlimited precision arithmetic. It takes input from any files
14 given, then reads the standard input. The -l argument stands for the
15 name of an arbitrary precision math library. The syntax for bc pro‐
16 grams is as follows; L means letter a-z, E means expression, S means
17 statement.
18 Comments
20 are enclosed in /* and */.
21 Names
23 simple variables: L
24 array elements: L [ E ]
25 The words `ibase', `obase', and `scale'
26 Other operands
28 arbitrarily long numbers with optional sign and decimal point.
29 ( E )
30 sqrt ( E )
31 length ( E ) number of significant decimal digits
32 scale ( E ) number of digits right of decimal point
33 L ( E , ... , E )
34 Operators
36 + - * / % ^ (% is remainder; ^ is power)
37 ++ -- (prefix and postfix; apply to names)
38 == <= >= != < >
39 = =+ =- =* =/ =% =^
40 Statements
42 E
43 { S ; ... ; S }
44 if ( E ) S
45 while ( E ) S
46 for ( E ; E ; E ) S
47 null statement
48 break
49 quit
50 Function definitions
52 define L ( L ,..., L ) {
53 auto L, ... , L
54 S; ... S
55 return ( E )
56 }
57 Functions in -l math library
59 s(x) sine
60 c(x) cosine
61 e(x) exponential
62 l(x) log
63 a(x) arctangent
64 j(n,x) Bessel function
65 All function arguments are passed by value.
67 The value of a statement that is an expression is printed unless the
69 main operator is an assignment. Either semicolons or newlines may sep‐
70 arate statements. Assignment to scale influences the number of digits
71 to be retained on arithmetic operations in the manner of dc(1).
72 Assignments to ibase or obase set the input and output number radix
73 respectively.
74 The same letter may be used as an array, a function, and a simple vari‐
76 able simultaneously. All variables are global to the program. `Auto'
77 variables are pushed down during function calls. When using arrays as
78 function arguments or defining them as automatic variables empty square
79 brackets must follow the array name.
80 For example
82 scale = 20
84 define e(x){
85 auto a, b, c, i, s
86 a = 1
87 b = 1
88 s = 1
89 for(i=1; 1==1; i++){
90 a = a*x
91 b = b*i
92 c = a/b
93 if(c == 0) return(s)
94 s = s+c
95 }
96 }
97 defines a function to compute an approximate value of the exponential
99 function and
100 for(i=1; i<=10; i++) e(i)
102 prints approximate values of the exponential function of the first ten
104 integers.
105 Bc is actually a preprocessor for dc(1), which it invokes automati‐
107 cally, unless the -c (compile only) option is present. In this case
108 the dc input is sent to the standard output instead.
109
111 /usr/lib/lib.b mathematical library
112 dc(1) desk calculator proper
113
115 dc(1)
116 L. L. Cherry and R. Morris, BC - An arbitrary precision desk-calculator
117 language
118
120 No &&, ||, or ! operators.
121 For statement must have all three E's.
122 Quit is interpreted when read, not when executed.
123 BC(1)