Why am I getting error "} expected" and how do I fix it?

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Hi,

I've been trying to write some code in visual studio's 2015 applications folder for a mini project. The aim of the task is to create a calculator for the heat conduction equation.

After managing to create a working calculator using the basics, I was then told to try and add a message box for when the input values of the calculator are invalid.

I did this by equating the input values to -1.0E-99 unless otherwise stated, however, when I tried to add in a message box statement the curly bracket before it (line 37) came up with an error reading "} expected".

After looking it up and adding curly brackets everywhere in the code to try and get rid of it, I'm still at a loss.

Does anyone please have a solution for me? I would greatly appreciate any advice you might have.

Thank you very much and many kind regards

What I have tried:

C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Heat_conduction_calculator_9
{
    public partial class Form1 : Form
    {
        double A, q, -k, T1, T2, x1, x2, Z;

        public Form1()
        {
            InitializeComponent();

            Z = -1.0E-99;
                -k = A = T1 = T2 = x1 = x2 = Z;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            x1 = double.Parse(textBox1.Text);
            T1 = double.Parse(textBox2.Text);
            x2 = double.Parse(textBox3.Text);
            T2 = double.Parse(textBox4.Text);
            k = double.Parse(textBox5.Text);
            A = double.Parse(textBox6.Text);
            if ((A >= Z) && (-k >= Z) && (x1 >= Z) && (x2 >= Z) && (T1 >= Z) && (T2 >= Z)) ;
            {
                q = (-1 * k * A * (T2 - T1) / (x2 - x1));
                textBox7.Text = q.ToString();
} //-----> line 37
            else if ((A <= Z)|(-k <= Z)|(x1 <= Z)|(x2 <= Z)|(T1 <= Z)|(T2 <= Z));
            MessageBox.Show("Invalid Input");

        }
                
    }
}

Posted 18-Mar-17 7:57am

Member 13068046

Updated 18-Mar-17 10:42am

Bryian Tan

v2

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Comments

Bryian Tan 18-Mar-17 14:11pm

By the way, was that a typos on the variable name -k ?

[no name] 18-Mar-17 14:27pm

Take the - off of k declaration and get rid of the ; at the end of your if statement.

2 solutions

Solution 1

You have two problems:
You can't name a variable -k. If you want it to be the negative of Z you just have to name it K and set it to -Z.
Secondly if statements don't have a ; at the end of them. That is effectively ending your if statment. Here is code that should do what you want:

C#

<pre>using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Heat_conduction_calculator_9
{
    public partial class Form1 : Form
    {
        double A, q, k, T1, T2, x1, x2, Z;

        public Form1()
        {
            InitializeComponent();

            Z = -1.0E-99;
            A = T1 = T2 = x1 = x2 = Z;
            k = -Z;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            x1 = double.Parse(textBox1.Text);
            T1 = double.Parse(textBox2.Text);
            x2 = double.Parse(textBox3.Text);
            T2 = double.Parse(textBox4.Text);
            k = double.Parse(textBox5.Text);
            A = double.Parse(textBox6.Text);
            if ((A >= Z) && (-k >= Z) && (x1 >= Z) && (x2 >= Z) && (T1 >= Z) && (T2 >= Z)) 
            {
                q = (-1 * k * A * (T2 - T1) / (x2 - x1));
                textBox7.Text = q.ToString();
            } //-----> line 37
            else if ((A <= Z) | (-k <= Z) | (x1 <= Z) | (x2 <= Z) | (T1 <= Z) | (T2 <= Z)) 
            MessageBox.Show("Invalid Input");

        }

    }
}

Posted 18-Mar-17 8:34am

takatok

Comments

Member 13068046 21-Mar-17 19:14pm

Thank you very much! I didn't spot that.

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Patrice T · Accepted Answer · 2017-03-18T10:42:00

C++

            if ((A >= Z) && (-k >= Z) && (x1 >= Z) && (x2 >= Z) && (T1 >= Z) && (T2 >= Z)) ;
            {
                q = (-1 * k * A * (T2 - T1) / (x2 - x1));
                textBox7.Text = q.ToString();
} //-----> line 37
            else if ((A <= Z)|(-k <= Z)|(x1 <= Z)|(x2 <= Z)|(T1 <= Z)|(T2 <= Z));
            MessageBox.Show("Invalid Input");

The 2 ";" at the end of the if line are mistakesn they are not C/C++, remove them.

Here is links to references books on C and C++ by the authors of the languages. Note than C is the ancestor of C++, so knowing C is always useful with C++.
The C Programming Language - Wikipedia, the free encyclopedia[^]
https://hassanolity.files.wordpress.com/2013/11/the_c_programming_language_2.pdf[^]
http://www.ime.usp.br/~pf/Kernighan-Ritchie/C-Programming-Ebook.pdf[^]

C++ Programing Language[^]