Lenght of int type

[Delcho]

Hello, can someone one tell me what is the easiest way to find the length of int type?

[Handy Andy]

Hello Delcho,

This should give you everything you need to know:

#include <iostream>

int main()
{
	std::cout << "bool:\t\t" << sizeof(bool) << " bytes" << std::endl;
	std::cout << "char:\t\t" << sizeof(char) << " bytes" << std::endl;
	std::cout << "wchar_t:\t" << sizeof(wchar_t) << " bytes" << std::endl;
	std::cout << "char16_t:\t" << sizeof(char16_t) << " bytes" << std::endl; // C++11, may not be supported by your compiler
	std::cout << "char32_t:\t" << sizeof(char32_t) << " bytes" << std::endl; // C++11, may not be supported by your compiler
	std::cout << "short:\t\t" << sizeof(short) << " bytes" << std::endl;
	std::cout << "int:\t\t" << sizeof(int) << " bytes" << std::endl;
	std::cout << "long:\t\t" << sizeof(long) << " bytes" << std::endl;
	std::cout << "long long:\t" << sizeof(long long) << " bytes" << std::endl; // C++11, may not be supported by your compiler
	std::cout << "float:\t\t" << sizeof(float) << " bytes" << std::endl;
	std::cout << "double:\t\t" << sizeof(double) << " bytes" << std::endl;
	std::cout << "long double:\t" << sizeof(long double) << " bytes" << std::endl;

	return 0;
}

This is old code, so some of the comments may not apply.

Hope that helps,

Andy

P.S. The sizes may be different on different computers.

[Delcho]

Thnks but somehow this doesn't work for me for example

int a=4; //lenhgt=1
cout<<sizeof(a)<<endl;  //it displays 4 not 1 

[Peter87]

It means that an int takes up 4 bytes of memory.

[Handy Andy]

Hello Delcho,

That is because the "sizeof()" is returning the size of "a" which is an "int" and on you computer an "int" is worth 4 bytes.

Change "a" to = 100 and see what you get. It would still say 4. Your example is a little misleading because you set "a" is equal to 4.

Hope that helps,

Andy

[Delcho]

Yes, I saw that but I want to understand how to find the length of an int type.
If we have variable a=123456 I want to understand its length i.e that it is six characters long.
Is there a function for this like the .size() for strings.

[goldenchicken]

No, but you can convert it to a string an get the length of it.

int a = 500468;
std::string len = std::to_string(a);
std::cout << len.length();

[lastchance]

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

#include <iostream> using namespace std; int intLength( int N ) { if ( N < 0 ) return 1 + intLength( -N ); else if ( N < 10 ) return 1; else return 1 + intLength( N / 10 ); } int main() { int a[] = { 123456, -345, 9, -5, 0 }; for ( int N : a ) cout << "The length of " << N << " is " << intLength( N ) << endl; }

The length of 123456 is 6 The length of -345 is 4 The length of 9 is 1 The length of -5 is 2 The length of 0 is 1

[Delcho]

Thanks!

[keskiverto]

Hello, can someone one tell me what is the easiest way to find the length of int type?

Thnks but somehow this doesn't work for me for example

int a=4; //lenhgt=1
cout<<sizeof(a)<<endl;  //it displays 4 not 1  

It seems that you did not ask what you actually wanted to know.

To us, the "length of int type" means how much memory is allocated for an object of type int. All ints have same length, because every int is int. The int can store 1 or -2147483648 with equal ease. Really big numbers the int cannot store at all.


Your example implies a different question: How many digits does a base 10 representation of an integer value have?


A basic type is not necessarily "same length" in every platform. See http://www.cplusplus.com/reference/limits/numeric_limits/ how to check values in your platform.

[jonnin]

(int) of (log base 10 of N + 1)

[Peter87]

I was close to posting this solution earlier.

cout << ceil(log10(a + 1)) << endl;

But I realized you would need to add extra code to handle the value 0 (even more if you want to handle negative values). I'm also not comfortable relying on exact values with floating point numbers.

I think goldenchicken's solution is nice for its simplicity.

cout << to_string(a).length() << endl;

If you want something more efficient, but still reliable, you can use integers to calculate the value using a loop, or using recursion as lastchance did.