# Education is not limited to just classrooms. It can be gained anytime, anywhere... - Ravi Ranjan (M.Tech-NIT)

Structure is used for collecting different data types together.Structure is Collection of different data types. There are different ways of calculating size of structure.

## Different ways of calculating size of structure

1. By observation
2. By Using sizeof Operator
3. Without using Sizeof Operator

### Way 1 : Calculate by adding Individual Sizes

```struct Book
{
int pages;
char name;
char author;
float price;
}b1;```

Calculating Size of Structure :

```Size = size of 'Pages' + size of 'Name' +
size of 'Author' + size of 'Price'
= 2 + 10 * 1 + 10 * 1 + 4
= 2 + 10 + 10 + 4
= 26
```

Important Note :

1. Add all the individual Size of Each Structure Member .
2. Character array requires Memory Equivalent to  (No_of_elements * Sizeof(char))
3. Float , Integer requires 4,2 bytes respectively in Case of Borland CC++ 3.0

### Way 2 : Using Sizeof Operator

Sizeof Operator is used to Calculate size of data type,variable,expression result.Syntax of sizeof is much like function, but sizeof is not a library function. Sizeof is C Operator.

```#include<stdio.h>

typedef struct b1 {
char bname;
int ssn;
int pages;
}book;

book b1 = {"Let Us C","1000",90};

int main()
{
printf("
Size of Structure : %d",sizeof(b1));
return(0);
}
```

Output :

```Size of Structure : 26
```

### Way3 : Without Using Sizeof Operator

```#include<stdio.h>

struct
{
int a1,a2;
char s1;
int *ptr;
int arr;
}a;

void main()
{
int start,last;
start = &a.a1;
last = &a.a1;
printf("
Size of Structure : %d Bytes",start-last);
}
```

We can evaluate size of structure without using sizeof operator. We can find difference between them to find size of structure.