A destructor is automatically called when the object is destroyed. A virtual destructor in C++ is used primarily to prevent resource leaks by performing a clean-up of the object.

All the features of C are similiar to C++ except some features, such as polymorphism, operator overloading which are supported in C++ but not in C language.

Both C and C++ language is similiar in their functionality but C++ provides with more tools and options.

It is necessary to understand some of the concepts used extensively in object oriented programming.These include

Objects
Classes
Data abstraction and encapsulation
Inheritance
Polymorphism
Dynamic Binding
Message passing

#include<stdio.h>
int main(){
  FILE *p,*q;
  char file1[20],file2[20];
  char ch;
  printf("\nEnter the source file name to be copied:");
  gets(file1);
  p=fopen(file1,"r");
  if(p==NULL){
      printf("cannot open %s",file1);
      exit(0);
  }
  printf("\nEnter the destination file name:");
  gets(file2);
  q=fopen(file2,"w");
  if(q==NULL){
      printf("cannot open %s",file2);
      exit(0);
  }
  while((ch=getc(p))!=EOF)
      putc(ch,q);
  printf("\nCOMPLETED");
  fclose(p);
  fclose(q);
 return 0;
}

#include<stdio.h>
int main(){
  int num,i,f,r,sum=0,temp;

  printf("Enter a number: ");
  scanf("%d",&num);
 
  temp=num;
  while(num){
      i=1,f=1;
      r=num%10;

      while(i<=r){
         f=f*i;
        i++;
      }
      sum=sum+f;
      num=num/10;
  }
  if(sum==temp)
      printf("%d is a strong number",temp);
  else
      printf("%d is not a strong number",temp);

  return 0;
}

Sample output:
Enter a number: 145
145 is a strong number

 #include<stdio.h>
int main(){
  int i=1,f=1,num;

  printf("Enter a number: ");
  scanf("%d",&num);

  while(i<=num){
      f=f*i;
      i++;
  }

  printf("Factorial of %d is: %d",num,f);
  return 0;
}

Sample output:
Enter a number: 5
Factorial of 5 is: 120

 #include<stdio.h>
int main(){
    int num,r,sum=0,temp;

    printf("Enter a number: ");
    scanf("%d",&num);

    temp=num;
    while(num){
         r=num%10;
         num=num/10;
         sum=sum*10+r;
    }
    if(temp==sum)
         printf("%d is a palindrome",temp);
    else
         printf("%d is not a palindrome",temp);

    return 0;
}

Sample output:
Enter a number: 131
131 is a palindrome

 #include<stdio.h>
int main(){
    int k,r;
    long int i=0l,j=1,f;

    //Taking maximum numbers form user
    printf("Enter the number range:");
    scanf("%d",&r);

    printf("FIBONACCI SERIES: ");
    printf("%ld %ld",i,j); //printing firts two values.

    for(k=2;k<r;k++){
         f=i+j;
         i=j;
         j=f;
         printf(" %ld",j);
    }
 
    return 0;
}

Sample output:
Enter the number range: 15
FIBONACCI SERIES: 0 1 1 2 3 5 8 13 21 34 55 89 144 233 377