Words i cant get the meaning

i came across with this few var declaration words i dont know what they do please explain me plz:

- Unsigned ( ex: unsigned int variable)

- Const ( ex: Const char variable )

- long ( ex: long int variable)

....


if anyone know what this mean please help me

Regards: Wyvern.

Ps: My Dragoons say "hi" to everyone.

A long int uses at least as much memory as an int. Usually, but not always, they both use 32 bits.

Every integer gets represented by a certain amount of bits. With an unsigned integer datatype, all combinations of the bits represent a positive number, whereas a signed integer uses about half the combinations to represent negative numbers.

A const variable cannot be altered.

Here's a list of C++ Keywords.

Quote:

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Originally Posted by Rashakil Fol

A const variable.

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oxymoron?

a combination of two terms with exact opposite meanings.

;)

I know we have to declare constants, and assign values, but they aren't really variables, the declaration is just a simpler way to make use of the value. ( like pi, try typing pi every time you need to use the value, declaring a constant and assigning the value is much simpler. )

Actually depending on the exact situation a const can be variable.

unsigned is a modifier that means that the value is positive only (no negative sign). This helps extend the upper limit for integer values.

long is a modifier that basically says to use another set of min ranges for integer values. Depending on the compiler this can have no affect.

const is a modifier that means you can't change the value of the variable. Now this isn't 100% because you can cast away the const and change the value under certain conditions.

Now the reason I said a const variable is because of this:

Code:

---

#include <iostream>

using namespace std;

void func(const int &x)
{
        int &y = const_cast<int&>(x);
        y = x + 5;
}

int main()
{
        int i;
        cin >> i;
        cout<<"Before: "<<i<<'\t';
        func(i);
        cout<<"After: "<<i<<endl;
}

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which can be usefull in avoiding mistakenly altering the value.
but is not the idea behind a constant to reduce the chances of keyboard errors in large values, such as pi, or a 18+ digit number?

anything you setup in your code you can change, including constants. I just think that declaring it a constant if you are going to be altering the value is wasted effort.

Well it also depends on how you define variables in programming. I think the majority defines it as a named location in memory that has a value. So saying const variable is perfectly legal since using the const keyword still creates a variable.

Now const itself has no idea, its a thing. My chair is a thing, it does not create ideas. I can use my chair to implement an idea of mine (say sitting on my butt)

Quote:

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anything you setup in your code you can change, including constants.

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First rule: Don't make absolute statements like that.

THANK U

the confusy part is not clear as water.

<3.E>

Quote:

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Originally Posted by Thantos

Actually depending on the exact situation a const can be variable.

unsigned is a modifier that means that the value is positive only (no negative sign). This helps extend the upper limit for integer values.

long is a modifier that basically says to use another set of min ranges for integer values. Depending on the compiler this can have no affect.

const is a modifier that means you can't change the value of the variable. Now this isn't 100% because you can cast away the const and change the value under certain conditions.

Now the reason I said a const variable is because of this:

Code:

---

#include <iostream>

using namespace std;

void func(const int &x)
{
        int &y = const_cast<int&>(x);
        y = x + 5;
}

int main()
{
        int i;
        cin >> i;
        cout<<"Before: "<<i<<'\t';
        func(i);
        cout<<"After: "<<i<<endl;
}

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