Program to find the numbers co prime to each other.

#include

#include



int exteuclid(int a,int b);



void main()

{

   int a[20],M=1,x[20],i,b[20],c[20],A[20],e,T,j,p=0;

     // M[0]=1;

   clrscr();

   printf("Enter the no of m's which must be co prime to each other\n");

   scanf("%d",&e);

   printf("Enter the values of m's\n");

   for(i=0;i   scanf("%d",&a[i]);        //taking input small m's....



     printf("Enter the values of A's\n");

     for(i=0;i      scanf("%d",&A[i]);     //taking input A's......







    for(i=0;i    {

    M=M*a[i];           //calculating M....

    }

     printf("M=%d\n",M);

    // T=M[i];

   for(i=0;i   {

     b[i]=M/a[i];        //calculating M1,M2,M3.....and so on..



   }

   for(i=0;i     printf("M%d=%d\t",i+1,b[i]);





	      for(i=0;i	       {

		 c[i]=exteuclid(a[i],b[i]); //calculating multiplicative inverse....



	       }

		for(i=0;i		 printf("MI%d=%d\t",i+1,c[i]);



		for(i=0;i		{

		x[i]=A[i]*b[i]*c[i];

		}

		for(i=0;i		{

		p=p+x[i];



		}

		p=p%M;







		printf("our unique value x=%d",p);













   getch();

}





      int exteuclid(int a,int b)

      {

      int A2, A1, B2, B1, A3, B3,T1,T2,T3,q, r = 1, t, x;



     A1 = B2 = 1;

     A2 = B1 = 0;

     A3 = a;

     B3= b;





     do

	  {

	  q = (A3/B3);

	  r = (A3% B3);

	  //printf("%d\t %d\t %d\t %d\t %d\t %d\t %d\t %d\n",

		  //  A1, A2, B1, B2, c, d, q, r);



	       T1=A1-q*B1;

	       T2=A2-q*B2;

	       T3=A3-q*B3;

	       A1=B1;

	       A2=B2;

	       A3=B3;

	       B1=T1;

	       B2=T2;

	       B3=T3;



	  } while(r !=1);

	  return(B2);

    }

characters read from file and save in new file

for(int c = 0; (c = fgetc (file)) = EOF;) 
( 
   if(c> = 10 & & c <= 300) 
     fputc (c, outfile); 
)

Given String is palindrome or Not.

 # include 
   # include 
   # include 
    void main(void)
     {
      clrscr();
      char st[20];
      int i,l,s,mid;
      printf(" Enter the string \n");
      gets(st);
     l=strlen(st);
     mid=l/2;
     for(i=0;i<=mid;i++)
         if (st[i]!=st[l-1])
         goto XX;
         else
         l=l-1;
         printf("the given string is palindrome \n");
         goto YY;
      XX:
printf("The given string is not palindrome\n");
     YY:;
     getch();
   }

Matrix Multiplication in C

# include 

# include 

void main (void)

   

    {

    int A[3][3],B[3,3],C[3][3];

   clrscr();

   printf(" Read matrix A \n");

     for (i=1;i<=3;i++)

       for(j=1;j<=3;j++)

         scanf("%d"&A[i][j]);



  printf(" Read matrix B \n");

     for (i=1;i<=3;i++)

       for(j=1;j<=3;j++)

         scanf("%d"&B[i][j]);



  for(i=1;i<3;i++)

    for(j=1;j<3;j++)

      {

        for(k=1;k        C[i][j]=C[i]+A[i][k] * B[K][J];

      }

    printf(" The product of A&B  matrix is C \n");

     for (i=1;i<=3;i++)

        {

               for(j=1;j<=3;j++)

               printf("%d"C[i][j]); 

               printf('/n');

       }

  getch();

  }

linked list in C

typedef struct
{
char fname[30];
char lname[30];
char MI;
}stud_name;

typedef struct
{
unsigned long idnum;
stud_name name;
char course [10];
int yr_level;
}studtype;

typedef struct
{
int grpnum;
char subj[24];
int time_sked;
int day;
int units;
char rmnum;
}
class_sked;

decimal number into binary number system

#include
#include
#include

void dec_bin(long int num)   // Function Definition
{
long int rem[50],i=0,length=0;
while(num>0)
 {
 rem[i]=num%2;
 num=num/2;
 i++;
 length++;
 }
printf("\nBinary number : ");
     for(i=length-1;i>=0;i--)
             printf("%ld",rem[i]);
}
//================================================
void main()
{
long int num;
clrscr();
 
 printf("Enter the decimal number : ");
 scanf("%ld",&num);

    dec_bin(num);   // Calling function

 getch();
}

Heapsort algorithm Program in C

 
#include  
#include 
 
 
#define uint unsigned int
 
typedef int (*compare_func)(int, int);

 
void heap_sort(int This[], compare_func func_pointer, uint len)
{
  /* heap sort */

  uint half;
  uint parents;

  if (len <= 1)
    return;

  half = len >> 1;
  for (parents = half; parents >= 1; --parents)
  {
    int tmp;
    int level = 0;
    uint child;

    child = parents;
    /* bottom-up downheap */

    /* leaf-search for largest child path */
    while (child <= half)
    {
      ++level;
      child += child;
      if ((child < len) &&
          ((*func_pointer)(This[child], This[child - 1]) > 0))
        ++child;
    }
    /* bottom-up-search for rotation point */
    tmp = This[parents - 1];
    for (;;)
    {
      if (parents == child)
        break;
      if ((*func_pointer)(tmp, This[child - 1]) <= 0)
        break;
      child >>= 1;
      --level;
    }
    /* rotate nodes from parents to rotation point */
    for (;level > 0; --level)
    {
      This[(child >> level) - 1] =
        This[(child >> (level - 1)) - 1];
    }
    This[child - 1] = tmp;
  }

  --len;
  do
  {
    int tmp;
    int level = 0;
    uint child;

    /* move max element to back of array */
    tmp = This[len];
    This[len] = This[0];
    This[0] = tmp;

    child = parents = 1;
    half = len >> 1;

    /* bottom-up downheap */

    /* leaf-search for largest child path */
    while (child <= half)
    {
      ++level;
      child += child;
      if ((child < len) &&
          ((*func_pointer)(This[child], This[child - 1]) > 0))
        ++child;
    }
    /* bottom-up-search for rotation point */
    for (;;)
    {
      if (parents == child)
        break;
      if ((*func_pointer)(tmp, This[child - 1]) <= 0)
        break;
      child >>= 1;
      --level;
    }
    /* rotate nodes from parents to rotation point */
    for (;level > 0; --level)
    {
      This[(child >> level) - 1] =
        This[(child >> (level - 1)) - 1];
    }
    This[child - 1] = tmp;
  } while (--len >= 1);
}

 
#define ARRAY_SIZE 250000
 
int my_array[ARRAY_SIZE];
 
void init()
{
  int indx;

  for (indx=0; indx < ARRAY_SIZE; ++indx)
  {
    my_array[indx] = rand();
  }
}
 
int cmpfun(int a, int b)
{
  if (a > b)
    return 1;
  else if (a < b)
    return -1;
  else
    return 0;
}
 
int main()
{
  int indx;
 
  init();
 
  heap_sort(my_array, cmpfun, ARRAY_SIZE);

  for (indx=1; indx < ARRAY_SIZE; ++indx)
  {
    if (my_array[indx - 1] > my_array[indx])
    {
      printf("bad sort\n");
      return(1);
    }
  }

  return(0);
}
 

Program to Calculate Edit Distance between Two Strings in C

#include 

#define MAXLEN 80

int findMin(int d1, int d2, int d3) 
{
   /*
    * return min of d1, d2 and d3.
    */
   if(d1 < d2 && d1 < d3)
       return d1;
   else if(d1 < d3)
       return d2;
   else if(d2 < d3)
       return d2;
   else
      return d3;
}

int findEditDistance(char *s1, char *s2) {
    /*
     * returns edit distance between s1 and s2.
     */
   int d1, d2, d3;

   if(*s1 == 0)
       return strlen(s2);
   if(*s2 == 0)
       return strlen(s1);
   if(*s1 == *s2)
       d1 = findEditDistance(s1+1, s2+1);
   else
       d1 = 1 + findEditDistance(s1+1, s2+1);    // update.
   d2 = 1+findEditDistance(s1, s2+1);                   // insert.
   d3 = 1+findEditDistance(s1+1, s2);                   // delete.

   return findMin(d1, d2, d3);
}

int main() {
    char s1[MAXLEN], s2[MAXLEN];

    printf("Enter string 1: ");
    gets(s1);

    while(*s1) {
        printf("Enter string 2: ");
        gets(s2);
        printf("Edit distance(%s, %s) = %d.\n", s1, s2, findEditDistance(s1, s2));
        printf("Enter string 1(enter to end): ");
        gets(s1);
    }

    return 0;
}

Link Between Array and Pointer

#include 
 
void main()
{
    
    const int size = 5;
    
    int list[size] = {2,1,3,7,8};
    
    int* plist = list;
 
    // print memory address of array elements
    for(int i = 0; i < size;i++)
    {
        printf("list[%d] is in %d\n",i,&list[i]);
    
    }
 
    // accessing array elements using pointer
    for(i = 0; i < size;i++)
    {
        printf("list[%d] = %d\n",i,*plist);
        
        /* increase memory address of pointer so it go to the next 
           element of the array */
        plist++;
    }
 
}

Program to show Concept of Pointers In C

int c = 10;
int c2 = 20;

/* define a pointer and points to an constant integer.
pc can point to another integer but you cannot change the 
content of it */

const int *pc = &c;

/* pc++; */ /* cause error */

printf("value of pc is %d\n",pc);

pc = &c2;

printf("value of pc is %d\n",pc);

/* define a constant pointer and points to an integer. 
py only can point to y and its memory address cannot be changed
you can change its content */

int y = 10;
int y2 = 20;

int const *py = &y;

*py++;/* it is ok */
printf("value of y is %d\n",y);

/* py = &y2; */ /* cause error */

Program to show Example of recursive function in C

# include
 
int factorial(unsigned int number)
{
    if(number <= 1)
        return 1;
    return number * factorial(number - 1);
}
void main()
{
    int x = 5;
    printf("factorial of %d is %d",x,factorial(x));
}

Program to show various way to pass arguments to function in C

#include
 
/* Program to show various way to pass arguments to function in C */
 
/* demonstrate pass by pointer */
void swap(int *x, int *y);

/* demonstrate pass by value */
void swap(int x, int y); 

/* demonstrate pass an array to the function */
void bubble_sort(int a[], int size);
 
void print_array(int a[],int size);
 
void main()
{
    int x = 10;
    int y = 20;
 
    
    printf("x,y before swapping\n");
    printf("x = %d\n",x);
    printf("y = %d\n",y);
    
    // pass by value
    swap(x,y);
 
    printf("x,y after swapping using pass by value\n");
    printf("x = %d\n",x);
    printf("y = %d\n",y);
 
    // pass by pointer
    swap(&x,&y);
 
    printf("x,y after swapping using pass by pointer\n");
    printf("x = %d\n",x);
    printf("y = %d\n",y);
 
    // declare an array
    const int size = 5;
    int a[size] = {1,3,2,5,4};
 
    printf("array before sorting\n");
    print_array(a,size);
    
    bubble_sort(a,size);
 
    printf("array after sorting\n");
    print_array(a,size);
 
 
}
 
 
/* functions implementation */
 
void swap(int *x, int *y){
    int temp = *x;
        *x = *y;
        *y = temp;
}
 
void swap(int x, int y){
    int temp = x;
        x = y;
        y = temp;
}
 
void bubble_sort(int a[], int size)
{
   int i,j;
   for(i=0;i<(size-1);i++)
      for(j=0;j<(size-(i+1));j++)
             if(a[j] > a[j+1])
                    swap(&a[j],&a[j+1]);
}
 
void print_array(int a[],int size)
{
 
    for(int i = 0;i < size; i++)
    {
        printf("%d\t",a[i]);
        printf("\n");
    }
}

a program demonstrates assignment operator in C

#include 
void main()
{
    int x = 10;
    
    /* demonstrate = operator */
    int y = x; 
    printf("y = %d\n",y);
 
    /* demonstrate += operator */
    y += 10;
    printf("y += 10;y = %d\n",y);
    /* demonstrate -= operator */
    y -=5;
    printf("y -=5;y = %d\n",y);
 
    /* demonstrate *= operator */
    y *=4;
    printf("y *=4;y = %d\n",y);
 
    /* demonstrate /= operator */
    y /=2;
    printf("y /=2;y = %d\n",y);
   
}

ompanion fgetline function which reads from an arbitrary file pointer in C

#include 

int fgetline(FILE *fp, char line[], int max)
{
int nch = 0;
int c;
max = max - 1;   /* leave room for '\0' */

while((c = getc(fp)) != EOF)
 {
 if(c == '\n')
  break;

 if(nch < max)
  {
  line[nch] = c;
  nch = nch + 1;
  }
 }

if(c == EOF && nch == 0)
 return EOF;

line[nch] = '\0';
return nch;
}

Now we could read one line from ifp by calling

char line[MAXLINE];
...
fgetline(ifp, line, MAXLINE);