Overview of Integer Types

To store integers (whole numbers), you can use the int data type.

main


              123456789
            
#include <iostream>

int main()
{
	int num = 1231;

	// Printing the number stored in num
	std::cout << "The value of num is: " << num;
}

As we said in the previous chapter, we specify the type of variable to inform the computer how much memory to allocate for holding it. To hold the int variable, the computer allocates 4 bytes.

Now, you can access the variable using its name (num in the above example), reassign its value, and perform mathematical operations on the num variable.

main


              12345678910111213
            
#include <iostream>

int main()
{
	int num = 1231;
	std::cout << "Initial value: " << num << std::endl;
  
	num = 150;
    std::cout << "New value: " << num << std::endl;
  
	num = num + 50;
    std::cout << "New value + 50: " << num << std::endl;
}

If you reassign the value of a variable, then the value in memory is overwritten.

You may have noticed that so far, all the values we assigned to int (1231, 150, 200) are less than 16 symbols in binary code, so they could be stored in two cells (bytes). However, the int data type always takes up 4 bytes. The unused space in memory is filled with zeros.

It is not a big problem when the value takes less space than the int type can store. Still, as we will soon, we can sometimes make it more memory-efficient by using only 2 bytes.
The real trouble begins when the value takes more than 4 bytes. In this case, we just cannot use the int type to store it.

Therefore, we can only use the int type for numbers that fit in 4 bytes. The range of values that fit in 4 bytes is **from -2,147,483,648 to 2,147,483,647.

Note

If the number exceeds -2,147,483,648 to 2,147,483,647 range, we must not use the int data type for storing it.

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Seção 2. Capítulo 1