C# Nested Loops
C# allows using another loop inside a loop. The following examples illustrate this concept.
Syntax
In C#Nested for loopSyntax of the statement:
for ( init; condition; increment )
{
for ( init; condition; increment )
{
statement(s);
}
statement(s);
}
In C#Nested while loopSyntax of the statement:
while(condition)
{
while(condition)
{
statement(s);
}
statement(s);
}
In C#Nested do...while loopSyntax of the statement:
do
{
statement(s);
do
{
statement(s);
}while( condition );
}while( condition );
One thing worth noting about nested loops is that you can nest any type of loop inside any other type of loop. For example, a for loop can be nested inside a while loop, and vice versa.
Example
The following program uses a nested for loop to find the prime numbers from 2 to 100:
Example
using System;
namespace Loops
{
class Program
{
static void Main(string[] args)
{
/* local variable definition */
int i, j;
for (i = 2; i < 100; i++)
{
for (j = 2; j <= (i / j); j++)
if ((i % j) == 0) break; // If found, it is not a prime number
if (j > (i / j))
Console.WriteLine("{0} is a prime number", i);
}
Console.ReadLine();
}
}
}
namespace Loops
{
class Program
{
static void Main(string[] args)
{
/* local variable definition */
int i, j;
for (i = 2; i < 100; i++)
{
for (j = 2; j <= (i / j); j++)
if ((i % j) == 0) break; // If found, it is not a prime number
if (j > (i / j))
Console.WriteLine("{0} is a prime number", i);
}
Console.ReadLine();
}
}
}
When the above code is compiled and executed, it produces the following result:
2 是质数 3 是质数 5 是质数 7 是质数 11 是质数 13 是质数 17 是质数 19 是质数 23 是质数 29 是质数 31 是质数 37 是质数 41 是质数 43 是质数 47 是质数 53 是质数 59 是质数 61 是质数 67 是质数 71 是质数 73 是质数 79 是质数 83 是质数 89 是质数 97 是质数
The prime numbers within 1000 are:
