Page 23 - PROGRAMMING IN C_Neat

There are four storage classes:
1. Automatic Variables:
 These variables are declared inside a function.
 General Form:

auto datatype variablename;

 Example:
main()
{
auto int a;
_ _ _
_ _ _
_ _ _
}

2. External Variables:
 These variables are declared outside all the functions.
 They are common to all the functions.
 Example:
int a;

main()
{
_ _ _
_ _ _
_ _ _
}

void xyz()
{
_ _ _
_ _ _
_ _ _
}

3. Static Variables:
 These variables retain their values until the end of the program.
 General Form:

static datatype variablename;

 Example:
static int a;

4. Register Variables:
 These variables are stored in the CPU registers.

 General Form:

register datatype variablename;

 Example:
register int a;
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