Mastering C# 2.0: Essential Knowledge Points
In this article, we will delve into the core concepts of C# 2.0, focusing on the foreach loop, goto statement, and exception handling.
The foreach Loop: A Powerful Iteration Tool
The foreach loop is a versatile iteration tool that allows you to traverse a collection of values. The syntax for the foreach loop is as follows:
foreach (variable cycle type in a set of variable values)
To use the foreach loop effectively, you must ensure that the type of the loop variable matches the type of the values in the collection. If not, you may need to display a conversion, and the loop variable will be a read-only variable.
The goto Statement: A Cautionary Tale
The goto statement can be used to jump to any statement, including jumping out of a loop. However, it is essential to note that the goto statement should be used sparingly, as it can lead to poor code readability and confusion. To use the goto statement, you must specify a label, and the statement will jump to that label.
Exception Handling: A Safety Net for Your Code
Exception handling is a crucial aspect of programming, as it allows you to handle errors that may occur during the execution of your program. When an exception occurs, the try block will be executed, followed by one or more catch statements to catch the exceptions. The finally statement will be executed regardless of whether an exception occurs.
A Code Example: Demonstrating the foreach Loop, goto Statement, and Exception Handling
Here is an example code snippet that demonstrates the use of the foreach loop, goto statement, and exception handling:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication2
{
class Program
{
static void Main(string[] args)
{
char[] ch;
ch = new char[6];
// for loop
for (int i = 0; i < 6; i++)
{
ch[i] = (char)(97 + i);
}
// foreach loop
foreach (char c in ch)
{
Console.Write("{0}", c);
}
Console.WriteLine();
Console.WriteLine("1 + 2 + ... 10 = {0}", intSum(10));
dev();
}
static int intSum(int n)
{
int sum = 0, i = 1;
begin:
if (i <= n)
{
sum += i;
i++;
goto begin; // goto statement
}
return sum;
}
static void dev()
{
double x, y, z;
Console.Write("belongs dividend:");
x = Convert.ToDouble(Console.ReadLine());
Console.Write("belongs divisor:");
y = Convert.ToDouble(Console.ReadLine());
try
{
z = x / y;
Console.WriteLine("the result is: {0}", z);
}
catch (Exception e)
{
throw new Exception("divisor is not 0");
}
finally
{
Console.WriteLine("I finally statement must be executed");
}
}
}
}
In this example, we use the foreach loop to iterate over an array of characters, and the goto statement to jump to a label within the intSum method. We also demonstrate exception handling using the try-catch-finally statement.
Conclusion
Mastering C# 2.0 requires a solid understanding of the foreach loop, goto statement, and exception handling. By following the guidelines and examples provided in this article, you will be well-equipped to tackle even the most complex programming tasks.