Zoho-Round-01

Pointers Strings Loops Complex and Nested Loops Control Flows

1. Output of this program?

#include <iostream>
using namespace std;
int main()
{
    int i, j, var = 'A';
    for (i = 5; i >= 1; i--) {
        for (j = 0; j < i; j++)
            printf("%c ", (var + j));
        printf("\n");
    }
    return 0;
}

Output:

A B C D E 
A B C D 
A B C 
A B 
A 

2. Output of the program?

#include <stdio.h>
void f(char**);
int main()
{
    char *argv[] = { "ab", "cd", "ef", "gh", "ij", "kl" };
    f(argv);
    return 0;
}
void f(char **p)
{
    char *t;
    t = (p += sizeof(int))[-1];
    printf("%s\n", t);
}

Output:

gh

3. Output of the following program?

#include <stdio.h>
void dynamic(int s, ...)
{
    printf("%d ", s);
}
int main()
{
    dynamic(2, 4, 6, 8);
    dynamic(3, 6, 9);
    return 0;
}

Output:

2 3 

4. Predict the output?

#include <stdio.h>
int main()
{
    void demo();
    void (*fun)();
    fun = demo;
    (*fun)();
    fun();
    return 0;
}
void demo()
{
    printf("program ");
}

Output:

program program 

5. Explain: What is the output of the following program?

#include <stdio.h>
int main()
{  
   char str1[] = "ZohoInterview";
   char str2[] = {'t', 'e', 's', 't', 't', 'e', 's', 't', '1'};
   int n1 = sizeof(str1)/sizeof(str1[0]);
   int n2 = sizeof(str2)/sizeof(str2[0]);
   printf("n1 = %d, n2 = %d", n1, n2);
   return 0;
}

Output:

n1 = 14, n2 = 9

Explanation:

• str1 is a null-terminated string, so its length is 14 (13 characters + 1 null terminator).
• str2 is an array of characters without a null terminator, so its length is 9.

6. Explain: Predict the Output

#include <stdio.h>
int main()
{
    char str[] = "Aptitude";
    printf("%s %s %s\n", &str[5], &5[str], str+5);
    printf("%c %c %c\n", *(str+6), str[6], 6[str]);
    return 0;
}

Output:

ude ude ude
u u u

Explanation:

• &str[5], &5[str], and str+5 all point to the 6th character of str, which is 'u'.
• *(str+6), str[6], and 6[str] all access the 7th character of str, which is 'u'.

7. Explain: Predict the output of the below program

#include <stdio.h>
#define SIZE(arr) sizeof(arr) / sizeof(*arr)
void fun(int* arr, int n)
{
    int i;
    *arr += *(arr + n - 1) += 10;
}
void printArr(int* arr, int n)
{
    int i;
    for(i = 0; i < n; ++i)
        printf("%d ", arr[i]);
}
int main()
{
    int arr[] = {10, 20, 30};
    int size = SIZE(arr);
    fun(arr, size);
    printArr(arr, size);
    return 0;
}

Output:

50 20 40 

Explanation:

• *arr (10) is increased by the value of *(arr + n - 1) (30) plus 10, resulting in 50.
• *(arr + n - 1) (30) is increased by 10, resulting in 40.
• The final array is {50, 20, 40}.

8. Explain: Print the output

#include <stdio.h>
struct st
{
    int x;
    struct st next;
};
int main()
{
    struct st temp;
    temp.x = 10;
    temp.next = temp;
    printf("%d", temp.next.x);
    return 0;
}

Output:

• This code will not compile because struct st contains a field of its own type, which is not allowed in C.

9. Explain: Identify the output of the following

union test
{
    int x;
    char arr[8];
    int y;
};
int main()
{
    printf("%d", sizeof(union test));
    return 0;
}

Output:

8

Explanation:

• The size of the union is determined by the size of its largest member. arr[8] is the largest member, occupying 8 bytes.

10. Output of the program

#include <stdio.h>
char *c[] = {"GeksQuiz", "MCQ", "TEST", "QUIZ"};
char **cp[] = {c+3, c+2, c+1, c};
char ***cpp = cp;
int main()
{
    printf("%s ", **++cpp);
    printf("%s ", *--*++cpp+3);
    printf("%s ", *cpp[-2]+3);
    printf("%s ", cpp[-1][-1]+1);
    return 0;
}

Output:

TEST sQuiz Z CQ

Explanation:

• **++cpp points to "TEST".
• *--*++cpp+3 points to "Z".
• *cpp[-2]+3 points to "ST".
• cpp[-1][-1]+1 points to "eksQuiz".

11. **Question 1:**
```cpp
#include <iostream>
using namespace std;

int a = 20;

int main() {
  int a = 10;
  std::cout << a << "" << ::a;
  return 0;
}

Output: 1020

12. Question 2:

#include<iostream>

void func(int *b){
    *b = 1;
}

int main() {
    int *a;
    int n;
    a = &n;
    *a = 0;
    func(a);
    std::cout << *a << std::endl;
    return 0;
}

Output: 1

13. Question 3:

#include <iostream>
using namespace std;

class Test {
    static int i;
    int j;
};

int Test::i;

int main() {
    cout << sizeof(Test);
    return 0;
}

Output: 4

14. Question 4:

#include <stdio.h>

int main() {
   int i;
   char ch[] = {'z','o','h','o'};
   char *ptr, *str1;
   ptr = ch;
   str1 = ch;
   i = (*ptr-- + ++*str1) - 10;
   printf("%d", i);
   return 0;
}

Output: 235

15. Question 5:

int main() {
    int a[10][10] = {{1,2},{3,4},{5,6},{7,8},{9,10}};
    int *p = a[3];
    int result = (*p + 2) * a[4][1] + (++*p) + (*p + 7);
    printf("%d", result);
    return 0;
}

Output: 113

16. Question 6:

#include <stdio.h>

void main() {
    int n = 21;
    int out = 1;
    while(n > 3) {
        n /= 2;
        out *= (n / 2);
    }
    printf("%d", n * out);
}

Output: 20

17. Question 7:

#include <stdio.h>

int main() {
    int n[] = {8,1,3,9,4};
    int j, *y = n;
    for(j = 0; j < 5; j++) {
        if(j % 2 == 0)
            *y++;
    }
    printf("%d", *y);
    return 0;
}

Output: 9

18. Question 8:

#include <stdio.h>

int main() {
    int x = 10;
    int y = 20;
    if(!(x ^ y))
        printf("0");
    else
        printf("1");
    return 0;
}

Output: 1

19. Question 9:

#include <stdio.h>

int main() {
    int a[10][10] = {{1,2},{3,4},{5,6},{7,8},{9,10}};
    int *p = a[3];
    int result = (*p + 2) * a[4][1] + (++*p) + (*p + 13);
    printf("%d", result);
    return 0;
}

Output: 119

20. Question 10:

#include <stdio.h>

int calc(int x, int *py, int **ppz) {
    int y, z;
    **ppz += 1;
    z = **ppz;
    *py += **ppz;
    y = *py;
    x += *py;
    return x + y + z;
}

void main() {
    int c, *b, **a;
    c = 5;
    b = &c;
    a = &b;
    printf("%d", calc(c, b, a));
}

Output: 35

21

switch(5)
{
    default:printf("five");
    case 1:printf("one");
}

Output: fiveone

Explanation: The default case gets executed since there's no matching case for 5. After default, execution falls through to case 1, resulting in printing fiveone.

22

if(101)
    printf("hai");
else
    printf("all");

Output: hai

Explanation: 101 is a non-zero value, which is considered true in C. Therefore, printf("hai"); is executed.

23

for(i=0;i<5;i++);
printf("%d",i);

Output: 5

Explanation: The semicolon after the for loop creates an empty loop body. After the loop, i is 5, which gets printed.

24

void main()
{
    int a=10,b=20,c=30;
    printf("%d%d");
}

Output: Undefined behavior.

Explanation: The printf function is missing the variables to be printed, leading to undefined behavior.

25

main()
{
    int i=0;
    switch(i)
    {
        case 0: i++;
                printf("%d", i);
        case 1:
                printf("%d", i);
        case 2:
                printf("%d", i);
    }
}

Output: 112

Explanation: case 0 increments i to 1, then falls through to case 1 and case 2, printing 1, 1, 2 in sequence.

26

#define SQR(x) (x*x)
main()
{
    int a, b=3;
    a = SQR(b+2);
    printf("%d", a);
}

Output: 11

Explanation: SQR(b+2) expands to (b+2*b+2), i.e., 3+2*3+2 = 3+6+2 = 11.

27

int main()
{
    int i;
    int arr[5] = {1};
    for(i = 0; i < 5; i++)
        printf("%d", i);
}

Output: 01234

Explanation: The loop prints the values of i from 0 to 4.

28

main()
{
    int x=0;
    if(x=0)
        printf("value of x is zero");
    else
        printf("value of x is not zero");
}

Output: value of x is zero

Explanation: if(x=0) assigns 0 to x, which is false. Thus, printf("value of x is zero"); gets executed.

29

main()
{
    int i=0;
    for(i=0; i<20; i++)
    {
        switch(i)
        {
            case 0: i+=5;
            case 1: i+=2;
            case 5: i+=5;
            default: i+=4;
                     break;
        }
        printf("%d", i);
    }
}

Output: 5111721

Explanation:

• i = 0: case 0 adds 5 → i = 5 falls through, case 1 adds 2 → i = 7, case 5 adds 5 → i = 12, default adds 4 → i = 16 then breaks.
• i = 16: default adds 4 → i = 20 then breaks.

30

main()
{
    int x=20,y=35;
    x = y++ + x++;
    y = ++y + ++x;
    printf("%d%d",x,y);
}

Output: 5729

Explanation:

• x = y++ + x++ → x = 35 + 20 → x = 55, y = 36, x = 21
• y = ++y + ++x → y = 37 + 22 → y = 59

31

void main()
{
    printf("\n98");
    printf("\b76");
    printf("\r54");
}

Output: \r54 (results depend on terminal).

Explanation: \b moves the cursor back, \r moves to the start of the line.

32

int main()
{
    int x=3;
    if(x==2); x=0;
    if(x==3) x++;
    else
    printf("x=%d",x);
}

Output: 1

Explanation: First if does nothing (semicolon); second if is false; else not executed.

33

int main()
{
    printf(" \" hai %% all \" ");
}

Output: " hai % all "

Explanation: Escape sequences print double quotes and percent sign.

34

int main()
{
    printf(5+"welcome");
}

Output: me

Explanation: Pointer arithmetic prints string starting from the 5th index.

35

int main()
{
    printf("%c", 5["welcomeall"]);
}

Output: a

Explanation: Equivalent to printf("%c", "welcomeall"[5]);.

36

int main()
{
    int x = printf("welcome");
    printf("%d", x);
}

Output: welcome7

Explanation: printf("welcome") returns 7 (number of characters printed).

37

int main()
{
    printf("%d", printf("%d", 1234));
}

Output: 12344

Explanation: Inner printf prints 1234 and returns 4, outer printf prints 4.

38

int main()
{
    int a[25] = {1,2,3,4,5};
    printf("%d", sizeof(a)/sizeof(int));
}

Output: 25

Explanation: sizeof(a) gives total bytes, divided by sizeof(int) gives array length.

39

void main()
{
    int b=12;
    switch(printf("%c%d", 't', b))
    {
        case 0: printf("Hello"); break;
        case 1: printf("Bye"); break;
        case 5: printf("Welcome"); break;
        default: printf("Hi");
    }
}

Output: t12Hi

Explanation: printf("%c%d", 't', b) prints t12 and returns 3 (3 characters printed). default case executes.