The logic behind the for loop

Question

I understand that the above question is not so specific, and there are response flows related to the loop.

I am new to programming, most of the response stream is more specific.

My question is:

What is the logic of a for loop and how should there be one approach to write a for loop?

In simple words: What do you think and before writing a for loop? Example: which variable is initialized, etc.

I have problems understanding the loop, your answers will surely help novice programmers like me ..

Thanks world

Answer 1

The most common form of a for loop uses a new variable as a loop and loop counter from zero to (but not including) the upper limit.

This loop will go from 0 to 9:

 for (int i = 0; i < 10; i++) { // code here } 

You can name a loop variable anything that makes sense. Unless you have a good name, the names i , j and k are the old convention for naming variables for small loops.

The point of using < 10 instead of <= 9 is that you loop more than ten elements. If you iterate over elements in an array, you use the length of the array in the condition:

 for (int i = 0; i < anArray.Length; i++) { // access anArray[i] } 

There are three statements inside the for loop. Initializer, loop condition, and post-update. The loop above creates the same code as if you were executing a loop with while :

 int i = 0; while (i < 10) { // code here i++; } 

You can put whatever you like into three statements in a for loop, but you should try to stick to this general form. This is how the for loop is usually used, and people will easily understand what the loop does.

Answer 2

Loop exists to re-execute a specific block of code (consisting of one or more commands).

You can determine how many times a code block will be executed, and inside the loop you can use the loop iterator as a regular local variable.

Whenever I need to run something several times, I just use loop-simple like this.

Usually loop iterators do not get a special name, x , i or n is ok.

These are my two cents, given in simple language - if you have a more specific question, edit your question with it and let us know by comment so that I can edit my answer with the answer.

Answer 3

when programming a for loop, it is used in those places where you must repeat the action several times when the number is known.

in C# you do this in syntax like this.

 for(int i = 0; i < 10 ; i++) { //here I am telling C# to run this loop while `i` is less than 10 where I am ////starting i from 0 and incrementing its value after each iteration by 1. so this loop //will run 10 times as i reaches from 0 to 9 and will stop as soon as i turns to 10 } 

you can also use a variable instead of the constant 10

for example, you can ask the user to tell how many times he wants to start the cycle and save it in the variable x , then you can start the cycle x times using the following code

 for(int i = 0 ; i < x ; i ++) { // if x = 5 loop will run five times } 

Answer 4

The for-loop construct is used when we want to execute a block of code a certain number of times. For example, suppose I want to print numbers from one to five on the console screen, here is a naive implementation:

 Console.WriteLine(1); Console.WriteLine(2); Console.WriteLine(3); Console.WriteLine(4); Console.WriteLine(5); 

This works great, but what if the requirements change, to say write numbers from one to one hundred? Here the for-loop helps:

 int max = 100; for (int i = 1; i <= max; i++) { Console.WriteLine(i); } 

Destruction:

• Initializer

  int i = 0; Sets the variable i to 0, which is the number of loops executed by the loop.

• condition

  i <= max; Perform the following iteration if i less than or equal to max .

• Step

  i++; Increases i after the code block has been executed, in pre-order for the next iteration.

Hope this helps.

Answer 5

It is also worth noting that for loops you do not need to count the variable up or down, it can do almost everything that follows the pattern that @aligray describes:

 for(MethodThatDoesSomething(); MethodThatReturnsBool(); MethodThatGetsCalledEveryStep()) { } 

is valid for a loop, for example.

you can even replicate the foreach loop with the for loop:

  var i = new int[ ] { 1, 2, 3 }; for( var enumerator = i.GetEnumerator( ); enumerator.MoveNext( ); ) { enumerator.Current.ToString( ); }