What is the output of the following C code

output 

4  2
6  2
2  0

Reverse bits of Byte

write a C function to reverse the bits of a Byte as example if we have variable unsigned char x=0x07=0b00000111 as input parameter after reversing its bits it would return 11100000

solution 

	#include <stdio.h>
	unsigned char reverse (unsigned char inbyte)
	{
	unsigned char outbyte=0;
	for(int i=0;i<=7;i++)
	{
	if(inbyte&(1<<i))
	{
	outbyte|=1<<(7-i);
	}
	else
	{
	continue;
	}
	}
	return outbyte;
	}
	int main(int argc, char** argv) {
	unsigned char x=1;
	unsigned char revx=reverse(x);
	printf("%d\n",revx);
	return (EXIT_SUCCESS);
	}

view raw rev.c hosted with ❤ by GitHub

Palindrome String

Write a C code to check a String is palindrome or not , Some palindrome strings examples are "a", dad", "radar", "madam", "abcba" etc.

solution

	#include <stdio.h>
	#include <string.h>
	int main()
	{
	// a program to check a string is palindrome or not
	char string[20];
	printf("Enter the string\n");
	gets(string);
	unsigned int i=0;
	unsigned int j=strlen(string)-1;
	unsigned int flag=0;
	while(i!=j)
	{
	if(string[i]==string[j]){i++,j--;continue;}
	else {flag=1;break;}
	}
	if(flag==0){printf("string is palindrome\n");}
	else if(flag==1){printf("string is not palindrome\n");}
	return 0;
	}

view raw palin.c hosted with ❤ by GitHub

From decimal to binary

Write a C program to convert an integer from decimal to binary , using logical bitwise operators

solution

	#include <stdio.h>
	int main()
	{
	unsigned int x;
	printf("enter any positive integer\n");
	fflush(stdout);
	scanf("%d",&x);
	//sizeof(int)=4 byte on my machine
	for(int i=0;i<=31;i++)
	{
	if(x&(0x8000>>i)){printf("%d",1);}
	else {printf("%d",0);}
	}
	return 0;
	}

view raw dtob.c hosted with ❤ by GitHub

what is the output

what is the output of this C code 

	#include <stdio.h>
	union temp
	{
	int a;
	char c;
	};
	int main()
	{
	union temp t={66,'A'};// initialize the union members
	printf("%d\t%c\n",t.a,t.c);
	printf("%d\n",sizeof(t));
	return 0;
	}

view raw union.c hosted with ❤ by GitHub

output:
66    B
4
Explanation:
union temp t={66,'A'};
this statement will initialize only the first member of the union x with 66 and the compiler will ignore the second value 'A', as one element is sufficient to initialize all union members as they share the same memory locations
sizeof(t) =4 size of largest element in memory location

what is the output of this C code

	#include <stdio.h>
	struct point
	{
	int x;
	int y;
	};
	struct notpoint
	{
	int x;
	int y;
	};
	int main()
	{
	struct point p1={10,20};
	struct point p2={-10,-20};
	p1=p2;
	printf("%d\t%d",p1.x,p1.y);
	struct notpoint p3={100,200};
	p3=p1;
	printf("%d\t%d",p3.x,p3.y);
	if(p3>p2)
	{
	printf("hello\n");
	}
	else
	{
	printf("C programming\n");
	}
	return 0;
	}

view raw s.c hosted with ❤ by GitHub

output :
compilation error in line 19 , as you can not assign two structures of different types
also there is a compilation error in line 21 as rational operators can not be applied on structures