sizeof operator – Computer Sir Ki Class


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sizeof operator

Datatype size is found by using the sizeof operator in c++

Learning Objectives

  • Understanding sizeof as an operator.

Source Code

TC++ #1750


Source Code

Run Output

Size of integer=4
Size of character=1

Code Understanding

int n=10; int si=sizeof(n);
Here si will contain the size which is occupied in memory by the variable n. Since n is an integer variable, it will occupy 4 bytes in most modern operating systems. In older systems it was 2 bytes.

char c=’a’; int sc=sizeof(c);
Here sc will contain the size occupied by variable c, which has earlier been defined as a character type variable. A single char is always defined as 1 byte.


  • Most modern compilers also support the char16_t and char32_t declaration which are 2 byte and 4 byte respectively.
  • The declaration wchar_t is compiler dependent, which can be 1 byte, 2 byte or more.The sizeof usage for many primitive data types can also be seen from following code sheet.
    Finding Size of CPP Data Types

Suggested Filename(s): sizeofop.cpp, operator-sizeof.cpp


CSKC| Created: 16-Dec-2017 | Updated: 31-Aug-2018|

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