increment and decrements in for loop

Question

In a for loop should I use only i++ or i-- operators ? OR can I also use i+10, i+20,i-20 ? I used i+10 in the increment place in the For loop , it is not getting executed.but when I use i++ , it is getting executed.so please help me solve this ! I tried for(i=0;i<=100;i+20) is it wrong ?

Answer 1

In C and C++ at least, the statement:

i + 20

is an expression statement - the expression is evaluated (or may not be if the optimiser figures out the result does not affect the observable behaviour of the program, which is likely) but otherwise ignored. In fact, the statement:

42

is also valid but equally useless.

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What you should be doing is one of:

i += 20
i = i + 20

That will work better in your loop because it actually modifies the loop control variable.

Answer 2

If this is Java then the correct syntax is

for(i=0;i<=100;i=i+20) 

Answer 3

Maybe like this in C#!

        for (int i = 0; i < 100; i = i+10)
        {
            Console.WriteLine(i);
        }

Answer 4

If you are using Java try this:

for(int i = 0; i<= 100; i+=20){
    System.out.println(i);
}

In Java i++ is equal to i = i + 1 .Thats why i + 20 doesnt work. so you must do something like i += 20 or i = i + 20 .

Answer 5

When you use for(int i = 20; i <= 100; i + 20) it mean that start loop with i = 0, each iteration do i + 20 operation, and do this while i <= 100. Operation i + 20 dont have effect to i and i don't canged. You must change i in this section. Write for(int i = 20; i <= 100; i = i + 20) or for(int i = 20; i <= 100; i += 20) to change i in each loop iteration.