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96 lines
2.5 KiB
Markdown
96 lines
2.5 KiB
Markdown
---
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language: bc
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contributors:
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- ["Btup"]
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filename: learnbc.bc
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---
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```bc
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/*This is a multi-
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line comment.*/
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# This is also a (one-line) comment! (in GNU bc).
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/*1. Variables and control structures*/
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num = 45 /*All variables save only doubles, and you cannot save
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string constants directly.*/
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num = 45; /*You can choose to add a semicolon after
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every statement. This is optional.*/
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/*Blocks are denoted using the {} operators(similar to C):*/
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while(num < 50) {
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num += 1 /*equivalent to num=num+1.
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a = a op b is equivalent to a op= b.*/
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}
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/*And there are ++(increment) and --(decrement) operators.*/
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/*There are 3 special variables:
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scale: defines the scale of the double numbers.
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ibase: defines the base of input.
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obase: defines the base of output.*/
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/*If clauses:*/
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hour = read() /*Input a number*/
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if(hour < 12) { /*Operators are exactly like C.*/
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print "Good morning\n" /*"print" outputs strings or variables
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separated by commas.*/
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} else if(hour == 12) {
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print "Hello\n"
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/*Escaping sequences start with a \ in a string.
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In order to make the escaping sequences clearer, here
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is a simplified list of them that will work in bc:
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\b: backspace
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\c: carriage return
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\n: newline
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\t: tab
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\\: backslash*/
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} else {
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print "Good afternoon\n"
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}
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/*Like C, only 0 is falsy.*/
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num = 0
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if(!num) {print "false\n"}
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/*Unlike C, bc does not have the ?: operators. For example,
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this block of code will cause an error:
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a = (num) ? 1 : 0
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However, you can simulate one:*/
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a = (num) && (1) || (0) /*&& is and, || is or*/
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/*For loops*/
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num = 0
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for(i = 1; i <= 100; i++) {/*Similar to the C for loop.*/
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num += i
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}
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/*2.Functions and Arrays*/
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define fac(n) { /*define a function using define.*/
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if(n == 1 || n == 0) {
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return 1 /*return a value*/
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}
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return n * fac(n - 1) /*recursion is possible*/
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}
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/*Closures and anonymous functions are impossible.*/
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num = fac(4) /*24*/
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/*This is an example of local variables:*/
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define x(n) {
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auto x
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x = 1
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return n + x
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}
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x(3) /*4*/
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print x /*It turns out that x is not accessible out of the function.*/
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/*Arrays are equivalent to the C array.*/
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for(i = 0; i <= 3; i++) {
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a[i] = 1
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}
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/*Access it like this:*/
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print a[0], " ", a[1], " ", a[2], " ", a[3], "\n"
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quit /*Add this line of code to make sure
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that your program exits. This line of code is optional.*/
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```
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Enjoy this simple calculator! (Or this programming language, to be exact.)
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This whole program is written in GNU bc. To run it, use ```bc learnbc.bc```.
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