C - Interview Questions and Answers

41) Write a program to print "hello world" without using a semicolon?

 #include<stdio.h>     void main(){      if(printf("hello world")){} // It prints the ?hello world? on the screen. }    

42) Write a program to swap two numbers without using the third variable?

 #include<stdio.h>     #include<conio.h>     main()     {     int a=10, b=20;    //declaration of variables. clrscr();        //It clears the screen. printf("Before swap a=%d b=%d",a,b);            a=a+b;//a=30 (10+20)      b=a-b;//b=10 (30-20)     a=a-b;//a=20 (30-10)          printf("\nAfter swap a=%d b=%d",a,b);     getch();     } 

43) Write a program to print Fibonacci series without using recursion?

 #include<stdio.h>   #include<conio.h>   void main()   {    int n1=0,n2=1,n3,i,number;    clrscr();    printf("Enter the number of elements:");    scanf("%d",&number);    printf("\n%d %d",n1,n2);//printing 0 and 1       for(i=2;i<number;++i)//loop starts from 2 because 0 and 1 are already printed    {     n3=n1+n2;     printf(" %d",n3);     n1=n2;     n2=n3;    }   getch();   }   

44) Write a program to print Fibonacci series using recursion?

 #include<stdio.h>     #include<conio.h>     void printFibonacci(int n) // function to calculate the fibonacci series of a given number. {     static int n1=0,n2=1,n3;    // declaration of static variables.     if(n>0){              n3 = n1 + n2;              n1 = n2;             n2 = n3;              printf("%d ",n3);              printFibonacci(n-1);    //calling the function recursively.     }     }     void main(){         int n;         clrscr();         printf("Enter the number of elements: ");         scanf("%d",&n);         printf("Fibonacci Series: ");         printf("%d %d ",0,1);         printFibonacci(n-2);//n-2 because 2 numbers are already printed         getch();     }     

45) Write a program to check prime number in C Programming?

 #include<stdio.h>     #include<conio.h>     void main()     {     int n,i,m=0,flag=0;    //declaration of variables. clrscr();    //It clears the screen. printf("Enter the number to check prime:");     scanf("%d",&n);     m=n/2;     for(i=2;i<=m;i++)     {     if(n%i==0)     {     printf("Number is not prime");     flag=1;     break;    //break keyword used to terminate from the loop. }     }     if(flag==0)     printf("Number is prime");     getch();    //It reads a character from the keyword. } 

46) Write a program to check palindrome number in C Programming?

 #include<stdio.h>   #include<conio.h>   main()   {   int n,r,sum=0,temp;   clrscr();   printf("enter the number=");   scanf("%d",&n);   temp=n;   while(n>0)   {   r=n%10;   sum=(sum*10)+r;   n=n/10;   }   if(temp==sum)   printf("palindrome number ");   else   printf("not palindrome");   getch();   }   

47) Write a program to print factorial of given number without using recursion?

 #include<stdio.h>   #include<conio.h>   void main(){     int i,fact=1,number;     clrscr();     printf("Enter a number: ");     scanf("%d",&number);        for(i=1;i<=number;i++){         fact=fact*i;     }     printf("Factorial of %d is: %d",number,fact);     getch();   }   

48) Write a program to print factorial of given number using recursion?

 #include<stdio.h>     #include<conio.h>      long factorial(int n)    // function to calculate the factorial of a given number.  {       if (n == 0)         return 1;     else     return(n * factorial(n-1));    //calling the function recursively. }      void main()     {       int number;    //declaration of variables.   long fact;      clrscr();       printf("Enter a number: ");     scanf("%d", &number);       fact = factorial(number);    //calling a function. printf("Factorial of %d is %ld\n", number, fact);      getch();   //It reads a character from the keyword.  } 

49) Write a program to check Armstrong number in C?

 #include<stdio.h>     #include<conio.h>     main()     {     int n,r,sum=0,temp;    //declaration of variables. clrscr(); //It clears the screen.    printf("enter the number=");     scanf("%d",&n);     temp=n;     while(n>0)     {     r=n%10;     sum=sum+(r*r*r);     n=n/10;     }     if(temp==sum)     printf("armstrong  number ");     else     printf("not armstrong number");     getch();  //It reads a character from the keyword. }   

50) Write a program to reverse a given number in C?

 #include<stdio.h>     #include<conio.h>     main()     {     int n, reverse=0, rem;    //declaration of variables. clrscr(); // It clears the screen.    printf("Enter a number: ");     scanf("%d", &n);     while(n!=0)     {          rem=n%10;          reverse=reverse*10+rem;          n/=10;     }     printf("Reversed Number: %d",reverse);     getch();  // It reads a character from the keyword.   }     

Interview :: C