How To Find The Size Of An Array In C

Get the Size of Array in C

Created: November-ten, 2020 | Updated: December-10, 2020

sizeof() Operator to Determine the Size of an Array in C
Get Length of Assortment in C

This tutorial introduces how to determine the length of an assortment in C. The sizeof() operator is used to become the size/length of an assortment.

`sizeof()` Operator to Determine the Size of an Array in C

The sizeof() operator is a compile-time unary operator. It is used to calculate the size of its operand. It returns the size of a variable. The sizeof() operator gives the size in the unit of byte.

The sizeof() operator is used for any information blazon such as primitives like int, bladder, char, and too not-primitives data type as an array, struct. It returns the retentiveness allocated to that data type.

The output may be different on different machines like a 32-bit system can bear witness different output and a 64-flake system can show different of the same data types.

Syntax of `sizeof()`:

              sizeof(operand)

The operand is a data-type or any operand.

`sizeof()` Operator for Primitive Data Types in C

This program uses an int, bladder every bit a archaic data blazon.

              #include <stdio.h>   int main(void)  {      printf("Size of char data type: %u\north",sizeof(char));      printf("Size of int data type: %u\n",sizeof(int));      printf("Size of bladder information type: %u\n",sizeof(bladder));      printf("Size of double data blazon: %u\n",sizeof(double));           return 0;  }

Output:

              Size of char data type: ane Size of int information type: 4 Size of float data type: iv Size of double data type: 8

Get Length of Array in C

If we dissever the array'due south total size by the size of the assortment element, we go the number of elements in the assortment. The programme is as beneath:

              #include<stdio.h>  int main(void)  {     int number[16];          size_t n = sizeof(number)/sizeof(number[0]);     printf("Total elements the array can hold is: %d\northward",north);          render 0; }

Output:

              Total elements the array can concur is: 16

When an array is passed equally a parameter to the part, it treats every bit a pointer. The sizeof() operator returns the pointer size instead of array size. So inside functions, this method won't piece of work. Instead, pass an additional parameter size_t size to indicate the number of elements in the array.

              #include<stdio.h> #include<stdlib.h>  void printSizeOfIntArray(int intArray[]); void printLengthIntArray(int intArray[]);  int principal(int argc, char* argv[]) {     int integerArray[] = { 0, ane, 2, three, 4, 5, vi };      printf("sizeof of the array is: %d\northward", (int) sizeof(integerArray));     printSizeOfIntArray(integerArray);          printf("Length of the array is: %d\n", (int)( sizeof(integerArray) / sizeof(integerArray[0]) ));     printLengthIntArray(integerArray);  }  void printSizeOfIntArray(int intArray[]) {     printf("sizeof of the parameter is: %d\n", (int) sizeof(intArray)); }  void printLengthIntArray(int intArray[]) {     printf("Length of the parameter is: %d\n", (int)( sizeof(intArray) / sizeof(intArray[0]) )); }

Output (in a 64-scrap Linux OS):

              sizeof of the array is: 28 sizeof of the parameter is: 8 Length of the array is: 7 Length of the parameter is: two

Output (in a 32-flake Windows Bone):

              sizeof of the array is: 28 sizeof of the parameter is: iv Length of the assortment is: vii Length of the parameter is: 1

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