#include <stdio.h>
long fibonacci(int n)
{
long f2 = 0,f1 = 1,f_old;
int i;
for(i =0;i<n;i++)
{
  f_old = f2;
  f2 = f2+f1;
  f1 = f_old;
}
return f2;
}

int main(void)
{
int n;
for(n=1;n<=10;n++)
{
  printf("%d term = %ld\n",n,fibonacci(n));
}
return 0;
}

#include <stdio.h>
long recursive_fibonacci(int n)
{
if(n<=1)
  return n;
else
  return(recursive_fibonacci(n-1)+ recursive_fibonacci(n-2));
}

int main(void)
{
int n;
for(n=1;n<=10;n++)
{
printf("%d term = %ld\n",n,recursive_fibonacci(n));
}
return 0;
}

#include <stdio.h>
long int factorial(int n)
{
 if(n == 0 | n == 1)
  return 1;
 else
  return(factorial(n-1)*n);
}

int main(void)
{
 int how_many = 0,i;
 printf("I want table of factorial upto :");
 scanf("%d",&how_many);

 for(i=0;i<=how_many;i++)
  printf("\n%d!\t=\t%ld\n",i,factorial(i));
 return 0;
}

#include <stdio.h>
int main(void)
{
int a = 10,*p = &a;
printf("Adress of pointer is %p or %lu  and is pointed to %d",p,p,*p);
return 0;
}

#include <stdio.h>
void swap(int *a, int *b)
{
int temp = *a;
*a = *b;
*b = temp;
}

int main(void)
{
int a = 10,b = 20;
printf("Before swap:\n%d = \t%p or %lu \n%d = \t%p or %lu\n\n",a,&a,&a,b,&b,&b);
swap(&a,&b);
printf("After swap:\n%d = \t%p or %lu\n%d = \t%p or %lu\n",a,&a,&a,b,&b,&b);
}

#include <stdio.h>
int main(void)
{
int SIZE;
printf("Enter number of subjects:\n");
scanf("%d",&SIZE);
int grades[SIZE];
double sum = 0.0;
int i;
printf("\nEnter your grades:\n");
for(i = 0; i<SIZE; i++)
  scanf("%d",&grades[i]);
printf("\nYour grades are:\n");
for(i = 0; i<SIZE; i++)
  printf("%d\t",grades[i]);
printf("\n\n");
                                                                       for(i = 0; i<SIZE; i++)
sum += grades[i];
printf("Your percentage is %.2f %\n\n",sum/SIZE);
return 0;
}

#include <stdio.h>
void swap(int *a,int *b)
{
 int temp = *a;
 *a = *b;
 *b = temp;
}

void print_array(int how_many,int data[],char *str)
{
 int i;
 printf("%s",str);

 for(i = 0;i < how_many;i++)
  printf("%d\t",data[i]);
}

void bubble(int data[],int how_many)
{
 int i,j;
 int go_on;
 for(i=0 ; i<how_many ;i++)
 {
  print_array(how_many,data,"\nInside bubble\n");
  printf("\nEnter a number to continue : ");
  scanf("%d",&go_on);
  for(j=how_many-1;j>i;j--)
   if(data[j-1] > data[j])
    swap(&data[j-1],&data[j]);
  }
 }

int main(void)
{
 int SIZE;
 printf("Enter no. of numbers you want to sort:");
 scanf("%d",&SIZE);
 int num[SIZE];
 printf("Enter %d digits which you want to sort:\n",SIZE);
 for(int i = 0; i<SIZE ; i++)
    scanf("%d",&num[i]);
 print_array(SIZE,num,"Numbers you entered:\n");
 printf("\n\n");
 bubble(num,SIZE);
 print_array(SIZE,num,"\n\nSorted numbers:\n");
 printf("\n\n");
 return 0;
}

#include <stdio.h>
void print_array(int how_many,int data[],char *str)
{
 int i;

 printf("%s",str);

 for(i=0;i<how_many;i++)
  printf("%d\t",data[i]);
}

void merge(int a[],int b[],int c[],int how_many)
{
 int i=0,j=0,k=0;

 while(i<how_many && j<how_many)
  if(a[i]<b[j])
   c[k++] = a[i++];
  else
   c[k++] = b[j++];
 while(i<how_many)
  c[k++] = a[i++];
 while(j<how_many)
  c[k++] = b[j++];
}

int main(void)
{
 const int SIZE = 5;
 int a[SIZE] = {45,57,69,81,93};
 int b[SIZE] = {44,56,68,80,92};
 int c[2*SIZE];
 print_array(SIZE,a,"My grades are:\n");
 printf("\n\n");
 print_array(SIZE,b,"More grades:\n");
 merge(a,b,c,SIZE);
 printf("\n\n");
 print_array(2*SIZE,c,"My sorted grades are:\n");
 printf("\n\n");
}

#include <stdio.h>
void print_array(int how_many,int data[],char *str)
{
 int i;

 printf("%s",str);

 for(i=0;i<how_many;i++)
  printf("%d\t",data[i]);
}

void merge(int a[],int b[],int c[],int how_many)
/* here a and b are of same size */
{
 int i=0,j=0,k=0;

 while(i<how_many && j<how_many)
  if(a[i]<b[j])
   c[k++] = a[i++];
  else
   c[k++] = b[j++];
 while(i<how_many)
  c[k++] = a[i++];
 while(j<how_many)
  c[k++] = b[j++];
}

void mergesort(int key[],int how_many)
/* how_many is in power of 2*/
{
 int j,k;
 int w[how_many];

 for(k=1;k<how_many;k*=2)
 {
  for(j=0;j<how_many;j+=2*k)
   merge(key+j,key+j+k,w+j,k);
  for(j=0;j<how_many;j++)
   key[j] = w[j];
 }
}

int main(void)
{
 int size,i;
 printf("Enter size of array:");
 scanf("%d",&size);
 int a[size];
 printf("Enter %d numbers:\n",size);
 for(i=0;i<size;i++)
  scanf("%d",&a[i]);
 print_array(size,a,"Numbers you entered:\n\n");
 printf("\n\n");
 mergesort(a,size);
 print_array(size,a,"Sorted numbers:\n\n");
 printf("\n\n");
}

#include <stdio.h>
enum day{sun,mon,tue,wed,thr,fri,sat};
typedef enum day day;

void print_day(day d)
{
 switch(d)
 {
  case sun:printf("Sunday\n");break;
  case mon:printf("Monday\n");break;
  case tue:printf("Tuesday\n");break;
  case wed:printf("Wednesday\n");break;
  case thr:printf("Thrusday\n");break;
  case fri:printf("Friday\n");break;
  case sat:printf("Saturday\n");break;
  default :printf("This is not a valid day\n");break;
 }
}

day next_day(day d)
{
 return((d+1)%7);
}
int main(void)
{
 day today = sun;
 print_day(today);
 print_day(next_day(today));
 print_day(10);
 return 0;
}

#include <stdio.h>
#include <assert.h>

int main(void)
{
 double a,b;
 while(1)
 {
  printf("Enter 2 number:");
  scanf("%lf %lf",&a,&b);
  assert(b!=0);
  printf("a/b = %0.3lf\n",a/b);
 }
 return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

typedef enum dept{HR, Sales, Research, Software, Executive} dept;
typedef struct employee{
    dept department;
    int annual_sal;
    unsigned int ssn;
} employee;

const char* dept_to_string(dept department) {
    switch(department) {
        case HR: return "HR";
        case Sales: return "Sales";
        case Research: return "Research";
        case Software: return "Software";
        case Executive: return "Executive";
        default: return "Unknown";
    }
}

int salary_gen(dept department)
{
    int base_salary;
    int offset = rand() % 10000;
    if(department == HR)
        base_salary = 100000;
    else if(department == Sales)
        base_salary = 30000;
    else if(department == Research)
        base_salary = 50000;
    else if(department == Software)
        base_salary = 60000;
    else
        base_salary = 80000; //for executive
    return base_salary + offset;
}

int main(void)
{
    srand(time(NULL)); // seed the random number generator
    struct employee emp[10];
    for(int i = 0; i < 10; i++)
    {
        emp[i].department = rand() % 5; // assign a random department
        emp[i].annual_sal = salary_gen(emp[i].department); // generate a random salary
        emp[i].ssn = rand() % 1000000000 + 100000000; // generate a random SSN

        printf("Department: %s\n", dept_to_string(emp[i].department));
        printf("Annual Salary: %d\n", emp[i].annual_sal);
        printf("SSN: %u\n", emp[i].ssn);
    }
}

#include <stdio.h>
#include <ctype.h>

#define MAX_LEN 1000                                                                                                  #define EMPTY -1
#define FULL MAX_LEN-1

typedef struct stack{char s[MAX_LEN];int top;} stack;

void reset(stack *stk){stk->top = EMPTY;}                                                                             void push(char c,stack *stk)
{
    stk->top++;
    stk->s[stk->top] = c;
}

char pop(stack *stk){return (stk->s[stk->top--]);}
char top(stack *stk){return (stk->s[stk->top]);}

int is_empty(const stack *stk){return (stk->top==EMPTY);}
int is_full(const stack *stk){return(stk->top==FULL);}

int main(void)
{
    stack stack_of_char;
    char *str = "i am alok";
    char str_back[10];
    int i=0;                                                                                                              reset(&stack_of_char);                                                                                                printf("Given string is: %s\n\nPushing to stack:\n\n",str);
    while(str[i]!='\0')
    {
        printf("%c\n",str[i]);
        push(str[i++],&stack_of_char);
    }
    i=0;
    while(!is_empty(&stack_of_char)&&i<10)
    {
        str_back[i++]=pop(&stack_of_char);
    }
    printf("\nPoping from stack:\n\n");
    i=0;
    while(i<10)
    {
        printf("%c\n",str_back[i]);
        i++;
    }
    printf("Reversed string is: %s\n",str_back);
    return 0;
}

#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

typedef struct list {
  int data; struct list *next;
} list;

int is_empty(const list *l) {
  return (l == NULL);
}
list* create_list(int d) {
  list* head = malloc(sizeof(list));
  head->data = d;
  head->next = NULL;
  return head;
}
list* add_to_front(int d, list *h) {
  list* head = create_list(d);
  head->next = h;
  return head;
}
list *array_to_list(int d[], int size) {
  list *head = create_list(d[0]);
  for(int i = 1; i < size; i++) {
    head = add_to_front(d[i], head);
  }
  return head;
}
void print_list(list *h, char *title) {
  printf("%s\n", title);
  while(h != NULL) {
  printf("%d :", h->data);
  h = h->next;
  }
}

int main(void) {
  list list_of_int;
  list* head = NULL;
  int data[6] = {0,1,2,3,4,5};
  head = array_to_list(data, 6);
  print_list(head, "Singly linked list:");
  printf("\n\n");
  return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void printfile(FILE *ifp)
{
    int c;
    rewind(ifp);
    while((c=getc(ifp))!=EOF)
        putc(c,stdout);
}

void encrypt(FILE *ifp,FILE *ofp)
{
    int c;
    rewind(ifp);
    while((c=getc(ifp))!=EOF){
        if((c>=65 && c<=77) || (c>=97&& c<=109))
            putc(c+13,ofp);
        else if((c>=78 && c<=90) || (c>=110 && c<=122))
            putc(c-13,ofp);
        else
            putc(c,ofp);
    }
}

void decrypt(FILE *ifp,FILE *ofp)
{
    int c;
    rewind(ifp);
    while((c=getc(ifp))!=EOF){
        if((c>=65 && c<=77) || (c>=97 && c<=109))
            putc(c+13,ofp);
        else if((c>=78 && c<=90) || (c>=110 && c<=122))
            putc(c-13,ofp);
        else
            putc(c,ofp);
    }
}

int main(int argc,char *argv[])
{
    FILE *ifp,*ofp;
    if(argc!=4){
        printf("Need executable,operation,input file,output file");
        exit(1);
    }
    ifp = fopen(argv[2],"r+");
    ofp = fopen(argv[3],"w+");
    if(strcmp(argv[1],"encrypt") == 0){
        printf("%s File before encryption :\n\n", argv[2]);
        printfile(ifp);
        printf("\n\n");
        encrypt(ifp,ofp);
        printf("%s file is encrypted into file %s.\n\n Encrypted text:\n\n", argv[2], argv[3]);
        printfile(ofp);
        printf("\n\n");
    }
    else if(strcmp(argv[1],"decrypt") == 0){
        decrypt(ifp,ofp);
        printf("%s file is decrypted into file %s.\n\nDecrypted text:\n\n", argv[2], argv[3]);
        printfile(ofp);
        printf("\n\n");
    } 
}

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define SIDES 6
#define R_SIDE (rand() % SIDES + 1)
int main(void)
{
    int trials;
    int d1, d2;
    int outcomes[13] = {0};
    const int n_dice = 2;
    srand(clock());
    printf("Enter number of trials: ");
    scanf("%d", &trials);
    for (int j = 0; j < trials; ++j)
        outcomes[(d1 = R_SIDE) + (d2 = R_SIDE)]++;
    printf("Probability:\n");
    for (int j = 2; j < n_dice * SIDES + 1; ++j)
        printf("j=%d p=%lf\n", j, (double)(outcomes[j]) / trials);
    return 0;
}

#include <stdio.h>
int main(void){
 int n;
 printf("Enter no. of lines:");
 scanf("%d",&n);
 for(int i=1;i<=n;i++){
  for(int j=1;j<=n;j++){
   if(i==j)
    printf("\\\\");
   else if(i==n+1-j)
    printf("/");
   else
    printf(" ");
   }
  printf("\n");
 }
 return 0;
}

#include <stdio.h>
#include <stdlib.h>

void tab_to_space(FILE *ifp, FILE *ofp) {
  int c;
  int space = 0,
  count = 0;
  rewind(ifp);
  while((c = getc(ifp)) != EOF) {
    if(c == '\t') {
      space = (8-(count%8));
      while(space != 0) {
        putc(' ', ofp);
        space--;
        count++;
      }
    } else {
      putc(c, ofp);
      ++count;
    }
    if(c == '\n')
     count = 0;

  }
}

int main(int argc, char *argv[]) {
  FILE *ifp,
  *ofp;
  if(argc != 3) {
    printf("Need ifp,ofp files");
    exit(1);
  }
  ifp = fopen(argv[1], "r");
  ofp = fopen(argv[2], "w");
  tab_to_space(ifp, ofp);
  fclose(ifp);
  fclose(ofp);
  return 0;
}