The document discusses loop constructs in C# programming. It covers the main loop types: for, while, and do-while loops. Examples are provided to illustrate each loop, showing how to iterate through code a specified number of times or until a condition is met. The break and continue statements are also explained, with examples showing how break terminates the current loop and continue skips to the next iteration. In summary, the document provides an overview of common loop structures in C# and examples of how to implement for, while, do-while, break, and continue control flows.

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Programming Language with
C_Sharp
Object-Oriented-Programming
Renas R. Rekany

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Loop control structure
1- Goals:
In this chapter you will learn:
 What is Loop Constructs in C#?
 How many types of looping statements in C sharp?
 How to use loop constructs in Programming?
H.M) Write a program in C# to enter 10 degrees, then find the Grade for each of
them.
2- Loop constructs
The loop constructs is used to execute a block of code until the condition becomes
expired. Loop constructs in C#, saves the programmer from writing code multiple
times that has repetitive in nature.
2.1 For Loop:

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Example 1:
OUTPUT
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
string a;
a = "aa";
for (int i = 0; i < 5; i++)
{
textBox1.Text = textBox1.Text + a;
textBox1.AppendText(Environment.NewLine);
}
}
}
}

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Example 2:
OUTPUT
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
int i,j;
for (i = 0; i < 5; i++)
{
for (j = 0; j < 5; j++)
textBox1.Text = textBox1.Text + i+j+" ";
textBox1.AppendText(Environment.NewLine);
}
}
}
}
H.W) Find the main diagonal, secondary diagonal, swap the rows to columns…

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2.2 While Loop:
Example 3:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
int num, r, i;
num = Convert.ToInt32(textBox1.Text);
i = 1;
while (i <= 10)
{
r = num * i;
textBox2.Text = textBox2.Text + r + "=" + num + "*" + i;
textBox2.AppendText(Environment.NewLine);
i += 1;
}
}
}
}

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2.3 Do-While Loop:
Note: must put semi-colon(;) at the end of while condition in do-while loop.
Example 4:
private void button1_Click(object sender, EventArgs e)
{
int num, r, i;
num = Convert.ToInt32(textBox1.Text);
i = 1;
do
{
r = num * i;
textBox2.Text = textBox2.Text + r + "=" + num + "*" + i;
textBox2.AppendText(Environment.NewLine);
i += 1;
} while (i <= 10);
}
Q) What's the different between the (While and Do_While loop)?

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Break:
The break is use in for, while, do-while, switch case. Break statement is used to
terminating the current flow of program and transfer controls to the next execution.
Continue:
The continue is use in for, while, do-while. The continue statements enables you to
skip the loop and jump the loop to next iteration.
continue break
for (int i=0;i<=5;i++)
{
if(i<=3)
continue ;
textBox1.Text = textBox1.Text + i;
textBox1.AppendText(Environment.NewLine);
}
4
5
for (int j = 0; j <= 5; j++)
{
if (j >= 3)
break ;
textBox2.Text = textBox2.Text + j;
textBox2.AppendText(Environment.NewLine);
}
0
1
2
EX:
Break
for (int i=1; i<=7;i++)
{
If (i==5)
Break;
Textbox1.text=textbox1.text+ i;
}
Output
1 2 3 4
Continue
For (int i=1; i<=7;i++)
{ if (i==5)
Continue;
Textbox1.text=textbox1.text+ i;
}
Output
1234 678910