ilikeheaps/expr-calc

Simple program for evaluating expressions.

expr-calc

Simple program in C for evaluating arithmetic expressions.

Overview:

1. operates on floating point numbers
2. expressions are composed of infix operators, parantheses, multi-argument functions and constants
3. each operation has a priority that defines operation precedence
4. can work either in interactive mode in which it evaluates each expression on the input (separated by line break) or evaluate expression given in program arguments

Usage

1. basic operations

All operations in expression have to be written explicitly (2(1+2) is wrong) and each label can mean only one operation (so there is no 'negation -', there is only 'subtraction -') 2. sequences

One can input a sequence of expressions separated by commas. Each of them will be evaluated and the result will be displayed. 3. functions

Functions can be called in two ways:

• f(expr1, expr2)
• f expr1 expr2

In the second case if the expressions contain any operators, they need to be wrapped in brackets as functions have higher priority than any operator.

Operators

1. multiplying: "*"
2. division: "/"
3. addition: "+"
4. subtraction: "-"
5. exponentiation: "^"

Functions:

1. square root: sqrt(expr)
2. square: sqr(expr)
3. factorial: fact(expr)
4. exponentiation: pow(expr1, expr2)

expr-calc's Issues

sqrt, sqr don't work in some cases

To reproduce:
compile with gcc (Ubuntu 4.8.4-2ubuntu1~14.04.3) 4.8.4 under Xubuntu 14.04 LTS with -std=c99
run, input sqrt(4)
desired output: 2, program output: 4
input 1+sqrt(4)
desired output: 3, program output: 3
input sqr(10)
desired output: 100, program output: 10
input sqr(10)+1
desired output: 101, program output: 101