See(C) Code

#include<stdio.h> int main() {  int n;    printf("Eneter number\n");  scanf("%d", &n);  if( !(n & (n-1))){     printf("%d is power of 2\n", n);     return 0;  }  printf("%d is not power of 2 \n", n);  return 0; }

/*  * C program to Simulate Implementation of  Linux *cat* command  * This program will not handle redirection  * you can try to improve this program to handle redirection of file contents  */ #include<stdio.h> #include<string.h> #define MAX_FILE_NAME_CHARS 255 int main(int argc, char *argv[]) {  FILE *fp;  char file_name[MAX_FILE_NAME_CHARS], ch;  int i;  /*   * after creating a.out, rename it as mycat for our own cat command   * and it usage is same as standard cat command   */  if(argc<1){     printf("Usage mycat <filename> \n");     return 0;  }  /*   * cat handles more than one file   * so we need this loop to handle all the files provided   * on command line   */  for(i=1; i<=argc;i++){     /* no need of copy but for understanding purpose, i have created      * str...

/*  * C99 has  support of variable arguments in macros statement  * (called variadic macro) just like variable argument function, Macros also   * can be of variable number of augments  * This program illustrate variadic macros  */ #include <stdio.h>   /*   * Simple Macro definition   * which allows to print whatever the way you want   *  in Macro definition "..." indicates variadic macro, OP() definition is    * mixture of named args and variable number of aguments, it is possible   * to have macro of complete variable number of args   * like DISPLAY in below example   */ #define OP(format, exp, ...)  printf(format, exp, ##__VA_ARGS__) #define DISPLAY(...)    printf(__VA_ARGS__) int main() {  int a=3, b=4, c=5;  OP("%s %d\n", "Result after add", a+b);  OP("%s %d %s %d\n", "Result after add", a+b+c, "Result after sub", a-b);  OP("%s\n", "This is tes...

/*  * Program to print Armstrong number between range m and n  * Armstrong  number is nothing but sum of cubes of digits of number is  * equal to the number  * ex: 153 is Armstrong number since 1^3+5^3+3^3=153  * there are very few numbers hold above property; execute   * below program to find all numbers  * b/w m and n  */ #include <stdio.h> void is_armstrong(int num) {   int sum=0, n, d;   n=num;   while(n){   d=n%10;  /* extract digits of number*/   sum=sum+(d*d*d);  /*take sum of them */   n=n/10;  }  if(sum == num)  /*sum is same as number then it is Armstrong number*/     printf("%d\n", sum); } int main() { int i,n,m; printf("Enter range \n"); scanf("%d%d", &m, &n);  for(i=m;i<=n;i++){    is_armstrong(i);  } return 0; }

/*  * Program to swap bit in given 32 bit Integer number  */ #include<stdio.h> int main() {  int a;  int b1, b2;  printf("Enter numbers \n");  scanf("%d", &a);  printf("Enter bit numbers to be swapped\n");  scanf("%d%d", &b1, &b2);  if(b1 >=31 || b2>=31){     printf("Invalid bit positions(valid are 0 - 31)\n");     return 0;  }    if((a&(1<<b1)) && !(a&(1<<b2))){     /* bit number b1 is set but b2 is not      * to swap just unset b1 and set b2      */       a=a & ~(1<<b1);       a=a | (1 << b2);  } else if(!(a&(1<<b1)) && (a&(1<<b2))){        /* bit b1 is not set(zero) and bit b2 is set         * so to swap set b1 and clear b2 ...

This is one of the interview question, beginners could note, below is one of the way how we can find size of structure without using sizeof operator in C It is explained with simple program as follows #include<stdio.h> struct test {  int a;  char c;  double d; }; int main() { struct test *p; int size=0; /*  * initialize struct pointer with  * zero after type casting it to of type (struct test *)  */ p=(struct test *)0; /* by adding one to p gives size of struct */ size =(int)(p+1); printf("without using sizeof %d\n", size); /* verify result with sizeof operator */ printf("with using sizeof %d\n", sizeof(struct test)); return 0; } same way we can find size of other variables as well :-)