Structure questions with explanation in c

(q) What will be output of following c code?

void main()

{

struct employee

{

unsigned id: 8;

unsigned sex:1;

unsigned age:7;

};

struct employee emp1={203,1,23};

clrscr();

printf("%d\t%d\t%d",emp1.id,emp1.sex,emp1.age);

getch();

}

Output: 203 1 23

We can access the data member in same way.

How bit data is stored in the memory:

Minimum size of structure which data member in bit is two byte i.e. 16 bit. This is called word size of microprocessor. Word size depends on microprocessor. Turbo c is based on 8086 microprocessor which word size is two byte.

Bits are filed in from right to left direction 8 bit for id,1 bit for sex and 7 bit for age.

(q) What will be output of following c code?

void main()

{

struct bitfield

{

unsigned a:5;

unsigned c:5;

unsigned b:6;

}bit;

char *p;

struct bitfield *ptr,bit1={1,3,3};

p=&bit1;

p++;

clrscr();

printf("%d",*p);

getch();

}

Output: 12

Explanation:

Binary value of a=1 is 00001 (in 5 bit)

Binary value of b=3 is 00011 (in 5 bit)

Binary value of c=3 is 000011 (in 6 bit)

In memory it is represented as:

Let address of bit1 is 500 which initialize to char pointer p. Since can is one byte data type so p++ will be 501. *p means content of memory location 501 which is (00001100) and its binary equivalent is 12. Hence output is 12.

(q) What will be output of following c code?

void main()

{

struct bitfield

{

signed int a:3;

unsigned int b:13;

unsigned int c:1;

};

struct bitfield bit1={2,14,1};

clrscr();

printf("%d",sizeof(bit1));

getch();

}

Output: 4

(q) What will be output of following c code?

void main()

{

struct bitfield

{

unsigned a:3;

char b;

unsigned c:5;

int d;

}bit;

clrscr();

printf("%d",sizeof(bit));

getch();

}

Output: 5

Note: (Actual output will 6 due to slack byte ,So Before executing this program first go to option menu then compiler then code generation then select word alignment then press OK)

(q) What will be output of following c code?

void main()

{

struct field

{

int a;

char b;

}bit;

struct field bit1={5,'A'};

char *p=&bit1;

*p=45;

clrscr();

printf("\n%d",bit1.a);

getch();

}

Output: 45

Nesting of structure:

Nesting of structure is possible i.e. we can declare a structure within another structure but it is necessary inner structure must declares structure variable otherwise we can not access the data member of inner structure.

Example:

void main()

{

struct world

{

int a;

char b;

struct india

{

char c;

float d;

}p;

};

struct world st ={1,'A','i',1.8};

clrscr();

printf("%d\t%c\t%c\t%f",st.a,st.b,st.p.c,st.p.d);

getch();

}

Output: 1 A I 1.800000

(q) What will be output of following c code?

void main()

{

struct india

{

char c;

float d;

};

struct world

{

int a[3];

char b;

struct india orissa;

};

struct world st ={{1,2,3},'P','q',1.4};

clrscr();

printf("%d\t%c\t%c\t%f",st.a[1],st.b,st.orissa.c,st.orissa.d);

getch();

}

Output: 2 p q 1.400000

Looping questions in c and answers

Looping questions and answers with explanation for written test exam and interview in c programming language

(1)

What will be output of following c code?

#include<stdio.h>

extern int x;

int main(){

    do{

        do{

             printf("%o",x);

         }

         while(!-2);

    }

    while(0);

    return 0;

}

int x=8;

EXPLANATION

---

(2)

What will be output of following c code?

        

#include<stdio.h>

int main(){

    int i=2,j=2;

    while(i+1?--i:j++)

         printf("%d",i);

    return 0;

}

EXPLANATION

---

(3)

What will be output of following c code?

#include<stdio.h>

int main(){

    int x=011,i;

    for(i=0;i<x;i+=3){

         printf("Start ");

         continue;

         printf("End");

    }

    return 0;

}

EXPLANATION

---

(4)What will be output of following c code?

#include<stdio.h>

int main(){

    int i,j;

    i=j=2,3;

    while(--i&&j++)

         printf("%d %d",i,j);

    return 0;

}

EXPLANATION

---

(5)What will be output of following c code?

#include<stdio.h>

int main(){

    static int i;

    for(++i;++i;++i) {

         printf("%d ",i);

         if(i==4) break;

    }

    return 0;

}

EXPLANATION

---

(6)What will be output of following c code?

#include<stdio.h>

int main(){

    int i=1;

    for(i=0;i=-1;i=1) {

         printf("%d ",i);

         if(i!=1) break;

    }

    return 0;

}

EXPLANATION

---

(7)What will be output of following c code?

#include<stdio.h>

int main(){

    for(;;) {

         printf("%d ",10);

    }

    return 0;

}

EXPLANATION

---

(8)What will be output of following c code?

        

#include<stdio.h>

int r();

int main(){

    for(r();r();r()) {

         printf("%d ",r());

    }

    return 0;

}

int r(){

    int static num=7;

    return num--;

}

EXPLANATION

---

(9)What will be output of following c code?

        

#include<stdio.h>

#define p(a,b) a##b

#define call(x) #x

int main(){

    do{

         int i=15,j=3;

         printf("%d",p(i-+,+j));

    }

    while(*(call(625)+3));

    return 0;

}

EXPLANATION

---

(10)

#include<stdio.h>

int main(){

    int i;

    for(i=0;i<=5;i++);

    printf("%d",i)

    return 0;

}

EXPLANATION

---

(11)What will be output of following c code?

#include<stdio.h>

int i=40;

extern int i;

int main(){

    do{

         printf("%d",i++);

    }

    while(5,4,3,2,1,0);

    return 0;

}

EXPLANATION

---

(12)What will be output of following c code?

#include<stdio.h>

char _x_(int,...);

int main(){

    char (*p)(int,...)=&_x_;

    for(;(*p)(0,1,2,3,4); )

         printf("%d",!+2);

    return 0;

}

char _x_(int a,...){

    static i=-1;

    return i+++a;

}

EXPLANATION

---

(13)What will be output of following c code?

#include<stdio.h>

int main(){

    int i;

    for(i=10;i<=15;i++){

         while(i){

             do{

                 printf("%d ",1);

                 if(i>>1)

                      continue;

             }while(0);

             break;

         }

    }

    return 0;

}

EXPLANATION

---

(14)How many times this loop will execute?

#include<stdio.h>

int main(){

    char c=125;

    do

         printf("%d ",c);

    while(c++);

    return 0;

}

EXPLANATION

---

(15)What will be output of following c code?

        

#include<stdio.h>

int main(){

    int x=123;

    int i={

         printf("c" "++")

    };

    for(x=0;x<=i;x++){

         printf("%x ",x);

    }

    return 0;

}