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C sizeof Keyword

❮ C Keywords


Example

Measure the memory size of different variables and types:

int myInt;
float myFloat;
double myDouble;
char myChar;

printf("%lu\n", sizeof(myInt));
printf("%lu\n", sizeof(myFloat));
printf("%lu\n", sizeof(myDouble));
printf("%lu\n", sizeof(myChar));
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Definition and Usage

The sizeof keyword is an operator which measures the amount of memory used by a variable or data type.

When a data type is specified it indicates how many bytes are needed to store data of that type.

When a variable is specified it indicates how many bytes of memory the variable occupies.


More Examples

Example

To count the elements in an array, divide the size of the array by the size of each element in the array:

int myNumbers[] = {10, 25, 50, 75, 100};
int length = sizeof(myNumbers) / sizeof(myNumbers[0]);

printf("%d", length);
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Related Pages

Read more about memory size in our C Memory Size Tutorial.

Read more about array size in our C Array Size Tutorial.


❮ C Keywords

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