Why write programs that don't modify variables?

Slews of bugs happen because variable have values you aren't expecting. To minimize this class of bugs I use a technique a lot of people find surprising. I try to only assign and never modify variables. In C++, I make almost all my variables const.

C++ people are now saying -- Um if all your values are const how do you write a for loop?

In C++ I can't help myself, I'm stuck with a variable modification eg:

for (size_t x=0;x<6;x++) printf("%d",x)

In python the for loop naturally iterates over a sequence so you don't need to modify a value:

for x in range(6): print x

In C#, you can use either the C++ syntax or a more python syntax via foreach:

for (int x=0;x<6;x++) Console.WriteLine(x);

or

foreach (var x in Enumerable.Range(0,6)) Console.WriteLine(x)

I use the foreach syntax which people initially find confusing. But its value starts to shine when using non zero starting values. Assume I need to generate 113 numbers starting at 27. Which statement do you find expresses it better.

for (int x=27;x<=139;x++) Console.WriteLine(x)

or

foreach (var x in Enumerable.Range(27,113)) Console.WriteLine(x)

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