SIRISHA SANAPATHI: June 2020

26.6.20

c program dynamic memory management

DYNAMIC MEMORY MANAGEMENT

void main()

{

int *a,n,i;

printf("How many numbers do u want to enter ");

scanf("%d",&n);

a=(int*)malloc(n*sizeof(int));

printf("Enter numbers:");

for(i=0;i<n;i++)

scanf("%d",a+i);

printf("the entered numbers are\n");

for(i=0;i<n;i++)

printf("%d\n",*(a+i));

free(a);

}

OUTPUT

How many numbers do u want to enter 5

Enter numbers

956

324

8562

0159

Entered numbers are

956

324

8562

159

c program using arrays

USING ARRAYS:

void main()

{

int a[100],n,i;

printf("How many numbers do u want to enter:");

scanf("%d",&n);

printf("Enter numbers:");

for(i=0;i<n;i++)

scanf("%d",&a[i]);

printf("The entered numbers are\n");

for(i=0;i<n;i++)

printf("%d\n",a[i]);

}

OUTPUT:

How many numbers do u want to enter:4

Enter numbers:23

The entered numbers are

call by address example 2

CALL BY ADRESSS EXAMPLE 2

void changeMe(int*a)

{

*a=72;

}

void main()

{

int a=145;

printf("Before :%d\n",a);

changeMe(&a);

printf("After : %d",a);

}

OUTPUT

Before:145

After:72

call by address /reference example 1

CALL BY ADDRESS/REFERENCE EXAMPLE 1:

void swap(int*a,int *b)

{

int t;

t=*a;

*a=*b;

*b=t;

}

void main()

{

int a=10,b=20;

printf("Before swapping : %d,%d\n",a,b);

swap(&a,&b);

printf("After swapping : %d,%d\n",a,b);

}

OUTPUT

Before swapping 10,20

After swapping 20,10

call by value

CALL BY VALUE:

void swap(int a,int b)

{

int t;

t=a;

a=b;b=t;

}

void main()

{

int a=10,b=20;

printf("Before swapping : %d,%d\n",a,b);

swap(a,b);

printf("After swapping : %d,%d\n",a,b);

}

OUTPUT

Before swapping : 10,20

After swapping :10,20

Explanation :the a,b in main() and swap() functions are different....

So the changes made to a and b in the swap() function has no affect on a and b of main().

c program on arthmetic example 2

POINTER ARTHMETIC EXAMPLE 2

void main()

{

int a=10,b=20;

int*p=&a,*q=&b;

printf("%u,%u\n",p,q);

printf("%u\n",p+2);

printf("%u\n",p-2);

/* printf("%u\n",p*2); */

printf("%u\n",q-p);

/*printf("%u\n",p+q); illegal */

}

OUTPUT

6356724,6356720

6356732

6356716

4294967295

c program for pointer arthmetic

POINTER ARTHMETIC

void main()

{

int a=15;

char ch='x';

float f=9.7;

int*p=&a;

char*q=&ch;

float*r=&f;

printf("Before incremention:%d,%c,%f\n",a,ch,f);

a++;

ch++;

f++;

printf("after incremention:%d,%c,%f\n\n",a,ch,f);

printf("Before incremention:%d,%c,%f\n",p,q,r);

p++;

q++;

r++;

printf("after incremention:%d,%c,%f\n",p,q,r);

}

Before incrementation: 15,x,9.7

After incrementation: 16,y,10.7

Before incrementation:100,200,300

After incrementation: 102,201,304

C program for the necessary of different pointers

WHY DIFFERENT TYPES FOR POINTERS

void main()

{

int a=4873;

char ch='p';

float f=2173.964;

int *p;

p=&a;

printf("%u\n",*p);

p=&ch;

printf("u\n",*p);

p=&f;

printf("%u",*p);

}

OUTPUT

4873

garbage

c program for address of and value at operators example 2

ADDRESS OF AND VALUE AT OPERATORS EXAMPLE 2

void main()

{

int a=35;

int*p;

int**q;

p=&a;

q=&p;

printf("%u\n",p);

printf("%u\n",q);

printf("u\n",*q);

printf("u\n",*p);

/* printf ("%u\n",*a); illegal */

printf("%u\n",**q);

/* printf("%u\n",**p); illegal */

printf("%u",*&p);

}

OUTPUT

6356728

6356724

6356728

C program for size of a pointer

SIZE OF A POINTER

void main()

{

int a=10;

char ch='x';

float f=9.7;

int *p=&a;

char*q=&ch;

float*r=&f;

printf("%d,%d,%d\n",sizeof(a),sizeof(ch),sizeof(f));

printf("%d,%d,%d",sizeof(p),sizeof(q),sizeof(r));

}

OUTPUT

4,1,4

2,2,2

c program for address of and value at operators

ADDRESS OF AND VALUE AT OPERATORS

void main()

{

int a=35;

int *p;

p=&a;

printf("%u\n",a);

printf("%u\n",&a);

printf("%u\n",p);

printf("%u\n",&p);

printf("%u\n",*p);

}

OUTPUT

6356732

6353732

6357328

c program for to print an address

HOW TO PRINT AN ADDRESS

void main()

{

int a=10;

printf("%d\n",a);

printf("%u",&a);

}

OUTPUT

6356732

19.6.20

c global variable

GLOBAL VARIABLE:

int i=78;

void fun1()

{

printf("%d\n",i);

}

void fun2()

{

int i= 45;

printf("%d\n",i);

}

void main()

{

printf("%d\n",i);

fun1();

fun2();

}

OUTPUT:

c register storage class specifier

void main()

{

for(i=1;i<=5;i++)

printf("I LOVE INDIA.\n");

}

OUTPUT

I LOVE INDIA.

c static storage class

STATIC STORAGE CLASS :

void fun()

{

static int a=10;

printf("%d\n",a);

a++;

}

void main()

{

fun();

}

OUTPUT:

c auto storage class

AUTO STORAGE CLASS

void fun()

{

int a=10;

printf("%d\n",a);

a++;

}

void main()

{

fun();

}

OUTPUT

c macro: where we can access a variable

WHERE WE CAN ACCESS A VARIABLE...

void main()

{

int a=10;

printf("%d\n",a);

{

int b=20;

printf("%d,%d\n",a,b);

}

printf("%d,%d",a,b); /*error: b not accesible */

}

EXPALNATION:

A variable defined in a block can be accessed in that block and all its inner blocks (i.r., a variable defined in a block cannot be accessed in its outer block).It is called as the scope of a variable .

c macro :where to define a variable

WHERE TO DEFINE A VARIABLE

void main()

{

int a=10;

printf("%d\n",a);

{

int b=20;

printf("%d",b);

}

OUTPUT:

c program enclosing the variable in the macro expansion

IMPORTANCE OF ENCLOSING THE VARIABLES IN THE MACRO EXPANSION WITHIN PARENTHESIS

#include<math.h>

#define MAC(x,y)sqrt(x*x+y*y)

float fun(int x,int y)

{

return sqrt(x*x+y*y);

}

void main()

{

int a=3,b=4;

float p,q,r,s;

p=fun(a,b);

q=fun(a+1,b+1);

r=MAC(a,b);

s=MAC(a+1,b+1);

printf("Using functions:%f,%f\n",p,q);

printf("Using macros:%f,%f",r,s);

}

OUTPUT

Using functions: 5.0000000,6.403124

Using macros 5.0000000,4.000000

c program on name less blocks

PROGRAM ON NAMELESS BLOCKS

void main()

{

int a=10;

printf("%d\n",a);

{

printf("Stella Maris school -Marripalem");

}

OUTPUT

Stella Maris School-Marripalem

c program on macros with arguments

PROGRAM ON MACROS WITH ARGUMENTS

#define PI 3.142857

#define AREA(x)PI*x*x

void main()

{

float r,a;

printf("Enter radius of a circle");

scanf("%f",&r);

a=AREA(r);

printf("AREA of the circle=%f",a);

}

OUTPUT

Enter radius of a circle 45

AREA of the circle6364.285645

program on macros with arguments

PROGRAM ON MACROS WITH ARGUMENTS

#define SUM(a,b) a+b

void main()

{

int a,b;

printf("Enter two numbers");

scanf("%d%d",&a,&b);

printf("Sum=%d",SUM(a,b));

}

OUTPUT:

Enter two numbers:30 20

Sum=50

program on macros example 3

PROGRAM FOR MACROS EXAMPLE 3

#define PI 3.142857

void main()

{

float r,a;

printf("Enter radius of a circle:");

scanf("%f",&r);

a=PI*r*r;

printf("Area of circle:%f",a);

}

OUTPUT:

Enter radius of circle: 3

Area of circle: 285713

program on macros example 2

PROGRAM FOR MACROS 2

#define TRUE 1

void main()

{

while(TRUE)

{

printf("This loop runs infinite times\n");

}

OUTPUT

This loop runs infinite times

This loop runs infinite times.....................

program on macros example 1

PROGRAM FOR MACROS EXAMPLE 1

#define NULL 0

void main()

{

char st[20];

int i;

puts("Enter a string:");

gets(st);

for(i=0;st[i]!=NULL;i++);

printf("length=%d",i);

}

OUTPUT:

Enter a string:

Sirisha

Length=7