public static double eval(final String str) {
return new Object() {
int pos = -1, ch;

    void nextChar() {
        ch = (++pos < str.length()) ? str.charAt(pos) : -1;
    }

    boolean eat(int charToEat) {
        while (ch == ' ') nextChar();
        if (ch == charToEat) {
            nextChar();
            return true;
        }
        return false;
    }

    double parse() {
        nextChar();
        double x = parseExpression();
        if (pos < str.length()) throw new RuntimeException("Unexpected: " + (char)ch);
        return x;
    }

    // Grammar:
    // expression = term | expression `+` term | expression `-` term
    // term = factor | term `*` factor | term `/` factor
    // factor = `+` factor | `-` factor | `(` expression `)` | number
    //        | functionName `(` expression `)` | functionName factor
    //        | factor `^` factor

    double parseExpression() {
        double x = parseTerm();
        for (;;) {
            if      (eat('+')) x += parseTerm(); // addition
            else if (eat('-')) x -= parseTerm(); // subtraction
            else return x;
        }
    }

    double parseTerm() {
        double x = parseFactor();
        for (;;) {
            if      (eat('*')) x *= parseFactor(); // multiplication
            else if (eat('/')) x /= parseFactor(); // division
            else return x;
        }
    }

    double parseFactor() {
        if (eat('+')) return +parseFactor(); // unary plus
        if (eat('-')) return -parseFactor(); // unary minus

        double x;
        int startPos = this.pos;
        if (eat('(')) { // parentheses
            x = parseExpression();
            if (!eat(')')) throw new RuntimeException("Missing ')'");
        } else if ((ch >= '0' && ch <= '9') || ch == '.') { // numbers
            while ((ch >= '0' && ch <= '9') || ch == '.') nextChar();
            x = Double.parseDouble(str.substring(startPos, this.pos));
        } else if (ch >= 'a' && ch <= 'z') { // functions
            while (ch >= 'a' && ch <= 'z') nextChar();
            String func = str.substring(startPos, this.pos);
            if (eat('(')) {
                x = parseExpression();
                if (!eat(')')) throw new RuntimeException("Missing ')' after argument to " + func);
            } else {
                x = parseFactor();
            }
            if (func.equals("sqrt")) x = Math.sqrt(x);
            else if (func.equals("sin")) x = Math.sin(Math.toRadians(x));
            else if (func.equals("cos")) x = Math.cos(Math.toRadians(x));
            else if (func.equals("tan")) x = Math.tan(Math.toRadians(x));
            else throw new RuntimeException("Unknown function: " + func);
        } else {
            throw new RuntimeException("Unexpected: " + (char)ch);
        }

        if (eat('^')) x = Math.pow(x, parseFactor()); // exponentiation

        return x;
    }
}.parse();

}

Docker is a container-based application framework, which wraps a specific application with all its dependencies in a container. Docker containers can easily to ship to the remote location on start there without making entire application setup. This tutorial will help you to install Docker on Debian 10 Buster Linux distribution. Step 1 – Prerequisites First …