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CPE263 Week 3
Week 3
const (Constant)
In C#, const is used to define a constant value that cannot be changed after it is initially set. When you use const, the value is evaluated at compile-time and cannot be modified during the runtime of the program.
Properties of const:
• The value assigned must be a constant (e.g., numbers, characters, or true/false).
• It cannot be assigned a complex computation or a value derived at runtime.
• The value of const must be assigned at the time of declaration.
Project 1
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 WindowsFormsApp1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
const double Pi = Math.PI;
private void btnCir1_Click(object sender, EventArgs e)
{
double radius, ans;
radius = Convert.ToDouble(txtRadius.Text);
ans = 2 * Pi * radius;
txtAns.Text = ans.ToString();
}
private void btnCir2_Click(object sender, EventArgs e)
{
double radius, ans;
radius = Convert.ToDouble(txtRadius.Text);
ans = Pi * radius * radius;
txtAns.Text = ans.ToString();
}
private void btnCir3_Click(object sender, EventArgs e)
{
double radius, ans;
radius = Convert.ToDouble(txtRadius.Text);
ans = 4 * Pi * radius * radius;
txtAns.Text = ans.ToString();
}
private void btnCir4_Click(object sender, EventArgs e)
{
double radius, ans;
radius = Convert.ToDouble(txtRadius.Text);
ans = ( 4.0 / 3.0 ) * Pi * radius * radius * radius;
txtAns.Text = ans.ToString();
}
}
}
Math Class
The Math class is part of the System namespace in C#, which contains various mathematical functions and constants that are used for calculations, such as logarithms, sine, cosine, squaring, etc.
Important functions in Math:
• Math.Abs(): Finds the absolute value
• Math.Pow(x, y): Raises x to the power of y
• Math.Sqrt(x): Finds the square root of x
• Math.Round(): Rounds a decimal number to the nearest integer
• Math.PI: Constant value for Pi (3.14159265358979)
• Math.Max(a, b): Finds the maximum between a and b
• Math.Min(a, b): Finds the minimum between a and b
• Math.Sin(), Math.Cos(), Math.Tan(): Trigonometric functions
Project 2
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 WindowsFormsApp2
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
double PI = Math.PI;
double y1, y2, y3, y4, y5, y6, y7;
y1 = Math.Sin(PI / 2);
y2 = Math.Cos(PI);
y3 = Math.Sin(3 * PI / 2); // sin(270)
y4 = Math.Tan(PI / 4); //tan(45)
y5 = Math.Log10(1000);
y6 = Math.Pow(2, 10); //2^10
y7 = Math.Sqrt(100); //√100
for (int i = 0; i < 7; i++) // Looping up to 7 because we have 7 variables
{
double value = 0; // Default value
switch (i)
{
case 0:
value = y1;
break;
case 1:
value = y2;
break;
case 2:
value = y3;
break;
case 3:
value = y4;
break;
case 4:
value = y5;
break;
case 5:
value = y6;
break;
case 6:
value = y7;
break;
}
MessageBox.Show($"y{i + 1} = {value}"); // Proper string interpolation
}
}
}
}
Project 3
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 WindowsFormsApp3
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void btnCal_Click(object sender, EventArgs e)
{
double deg, cal;
deg = Convert.ToDouble(txtDeg.Text);
cal = 5 * (deg - 32) / 9;
//txtDeg.Text = cal.ToString();
MessageBox.Show(cal.ToString());
}
private void btnFar_Click(object sender, EventArgs e)
{
double deg, far;
deg = Convert.ToDouble(txtDeg.Text);
far = (9.0 / 5.0 )* deg + 32;
//txtDeg.Text = far.ToString();
MessageBox.Show(far.ToString());
}
}
}
PictureBox
C# statement that assigns the file path of an image to a PictureBox control in a Windows Forms application.
• pictureBox1: This is the name of the PictureBox control. A PictureBox is a UI component in Windows Forms that is used to display images.
• ImageLocation: This property of PictureBox specifies the path or URL to the image that will be displayed. By setting this property, the PictureBox will load the image from the given path.
• Application.StartupPath: This is a property in C# that returns the directory path where the executable file of the application is located. It’s useful when referencing resources stored in the same directory as the application itself.
• “\\sunset.jpg”: This is the relative path to the image file named sunset.jpg, located in the root folder of the application (since it is appended to Application.StartupPath).
Project 4
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 testPicture
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
pictureBox1.ImageLocation = Application.StartupPath + "\\waterfall.jpg";
}
private void button2_Click(object sender, EventArgs e)
{
pictureBox1.ImageLocation = Application.StartupPath + "\\sunset.jpg";
}
}
}