C Programming MCQ Questions and Answers on Data Types and Storage Classes 2

Yes. A C Variable should have both Type and Storage Class.

Eg.

int a=5; //By default its Storage Class is auto.
auto int b=10;

int a=5; // auto is by default
auto int b=10; // storage class auto is explicitly mentioned.

Only a register variable is stored in CPU Memory called Registers. Other variables are stored in RAM.

Yes. Registers are part of a CPU to store variable whose value changes frequently. Loop variables for example.

register int i=1;
while(i = 10)
{
	printf("i=%d\n", i); 
}

#include<stdio.h>

#include<myutils.c>

void myshow();
int a=10; // a is a global variable.
//Notice that there is no 'extern' keyword.
void main()
{
	printf("a=%d ", a);
	a = a + 1;
	myshow();
	show();

}

void show()
{
	printf("a=%d ", a);
}

//myutils.c file
//here we used extern to inform compiler
//about possible definition somewhere
extern int a;
void myshow()
{
	printf("a=%d ", a);
	a++;

}

//Output is 10 11 12

#include<stdio.h>
static int a=15;
void myshow();
int main()
{
	printf("%d", a);
	myshow();
	return 0;
}


//myutils.c file
extern int a;
void myshow()
{
	printf("%d", a);
}


//Compiler error.
//You can not use static global varible outside of file

Yes. CPU register can not store anything more than 16 bits or 2 bytes. You will not any compiler errors. It will be treated just like an auto Storage Class variable.

int a; //Definition. Allocates memory.

extern int b; //Does not allocate memory.