for

Loops 20 times, from 1 to 20

for (int i = 1; i <= 20; i++) 
{ 
   break;  //terminates the closest ending loop or switch 
} 

Loops 10 times, starting from 0 to 19, increment by 2

for (int i = 0; i < 20; i += 2) 

for (reverse)

If you want to decrement by 1

for (int i = 20; i > -1; i--) 
{ 
} 

Loops 10 times, starting from 20 to 1, decrement by 2

for (int i = 20; i > 0; i -= 2) 

Break

This will jump out of the loop when i is equal to 4.

for (int i = 0; i < 10; i++) 
{ 
  if (i == 4) 
  { 
    break; 
  } 
  Console.WriteLine(i); 
} 

Continue

The continue statement transfers execution to the next iteration within the loop

for (int i = 2; i <=10; i++) 
{ 
   if (i = 6) 
   { 
      continue; 
   } 
} 

Single Statement

When you only have a single statement the curly bracket is optional.

No Statements

You can have a for loop with no statements. This is like a while true loop

for (; ; ) 
{ 
} 

Example - With An Array

Using it with an array

string[] myArray = { "one", "two", "three" } 
for (int i = 0; i < myArray.Length; i++) 
{ 
   Console.Write(myArray[i]); 
} 

Example - Through Lowercase Letters

for (char c = 'a'; c <= 'z'; c++) 
{ 
    Console.WriteLine(c); 
} 

Example - Two Variables at Once

for (int i = 0, x = 0; i < 10 && x >= -2; i++, x--) 
{ 
    System.Console.WriteLine("for loop: i={0}, x={1}", i, x); 
}