14.Computer memory

 

Computer memory:

RAM is the primary, main or conventional memory of computer.

It is used to store the data, instructions and intermediate results.

It is a volatile memory, looses its data on termination of program or function.

The total memory is divided into number of bytes.

Each byte is divided into 8 bits.

Every byte is identified with a number called address (It is a positive number).

 

 

 

Scale of memory:

 

1 byte	8 bits
1024 bytes	1 Kilo Byte(KB)
1024 KB	1 Mega Byte(MB)
1024 MB	1 Giga Byte(GB)
1024 GB	1 Tera Byte(TB)

 

Data types in C Language:

 

C language is rich in data types, provides number of data types to allocate the memory of different types of different ranges.

Total data types in C language are classified into

Primary data types.

Derived data types.

User defined types.

In this session we are discussing the primary data types. 

Primary data types in C language:

The primary data types in C language are classified into

 

 

 

 

 

 

   

int:

It is the primary type in C language used to store integer constant.

It takes two bytes of memory (16 bits)

The higher most bit is used to store the sign. 0 for + and 1 for –

Left all the 15 bits are used to store actual value in a binary format.

When an integer is assigned to the variable, then it will be first converted into its binary equal and stores into the memory.

Range of integer is -32768 to 32767 (-2¹⁵ to +2¹⁵-1)

%d is used as the representation character for integers.

Example: (Integer representation)

 

 

 

 

 

 

 

 

 

 

 

 

 

    

Example explained:

Though int type cannot store more than 40000, unsigned int is capable to store 40000. Because, the range of unsigned int is double to the int.

The output of y is not as we expected, because, unsigned type cannot handle negative values.

 

float, double, long double:

These are the floating point types used to store the real constants of different ranges.

float takes 4 bytes, double takes 8bytes and long double takes 10 bytes of memory.

The range of float is 3.4x10^-38 to 3.4x10⁺³⁸, double is 1.7x10^-308 to 1.7x10⁺³⁰⁸ and long double is 3.4x10^-4932 to 1.1x⁺⁴⁹³² .

Representation character to float is %f, double is %lf and long double is %Lf.