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Data types

Declaration of variable names does two things

  • it tells the compiler what the variable name is
  • specifies what type of data the variable will hold

So it is mandatory that each variable should belong to a particular data type. C supports different data types like integer, character, float, double, etc.

Data type Size on a 16 bit machine Range
char 1 byte or 8 bits -128 to 127
signed char 1 byte -128 to 127
unsigned char 1 byte 0 to 255
short int or short 1 byte -128 to 127
int 2 bytes -32768 to 32767
unsigned int 2 bytes 0 to 65535
long int or long 4 bytes -2,147,483,648 to 2,147,483,647
unsigned long int 4 bytes 0 to 4,294,967,295
float 4 bytes 3.4E-38 to 3.4 E+38
double 8 bytes 1.7E-308 to 1.7E+308
long double 10 bytes 3.4E-4932 to 1.1E+4932

Example of declaring variables

int a=20,b=20,c;

int a=10;

int b=9;

int c=20;

float c=3.5;

char a =’A’;

long int al or long a;

short int b or short b;

double c;

long double c;

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