bc

bc is a language that supports arbitrary precision numbers with interactive execution of statements. There are some similarities in the syntax to the C programming language. A standard math library is available by command line option. If requested, the math library is defined before processing any files.

• bc [EN] @ Fedora Package
• bc [EN] @ Homebrew Formula

• bc [EN] @ Wikipedia
• bc [DE] @ Wikipedia

Documentation

• man 1 'bc' [EN]

Syntax

bc [PARAMETER ...] [FILE ...]

Parameters

-l, --mathlib

Define the standard math library.

Examples

int()

Integer part of a float number

bc -l << EOS
   define int(x) {
      s = scale; scale = 0; x /= 1; scale = s; return x
   }

   x =  2.25; int(x)
   x = -2.25; int(x)
EOS

Output:

 2
-2

ceiling()

bc -l << EOS
   define int(x) {
      s = scale; scale = 0; x /= 1; scale = s; return x
   }

   define ceiling(x) {
      auto r; r = int(x); if (r < x) r += 1; return r
   }

   x =  2.25; ceiling(x)
   x = -2.25; ceiling(x)
EOS

Output:

 3
-2

floor()

bc -l << EOS
   define int(x) {
      s = scale; scale = 0; x /= 1; scale = s; return x
   }

   define ceiling(x) {
      auto r; r = int(x); if (r < x) r += 1; return r
   }

   define floor(x) {
      return -ceiling(-x)
   }

   x =  2.25; floor(x)
   x = -2.25; floor(x)
EOS

Output:

 2
-3

round()

bc -l << EOS
   define int(x) {
      s = scale; scale = 0; x /= 1; scale = s; return x
   }

   define round(x) {
      if (x < 0) x -= 0.5 else x += 0.5; return int(x)
   }

   x =  2.25; round(x)
   x = -2.25; round(x)
   x =  2.75; round(x)
   x = -2.75; round(x)
EOS

Output:

 2
-2
 3
-3

round_to()

bc -l << EOS
   define int(x) {
      s = scale; scale = 0; x /= 1; scale = s; return x
   }

   define round(x) {
      if (x < 0) x -= 0.5 else x += 0.5; return int(x)
   }

   define round_to(x,y) {
      return y * round(x / y)
   }

   y =  250                     /* Round to 250 */
   x = 1122; round_to(x, y)
   x = 1144; round_to(x, y)

   y = 0.05                     /* Round to 0.05 */
   x = 2.22; round_to(x, y)
   x = 2.23; round_to(x, y)
EOS

Output:

1000
1250
2.20
2.25