Role-specific Data Structure Arrays Interview Questions & Answers:

1. What is Array?

An array is a series of elements. These elements are of the same type. Each element can be individually accessed using an index. For e.g an array of integers. Array elements are stored one after another (contiguous) in the memory. An array can have more than one dimension. First element in an array starts with 0.

2. What is two-dimensional array?

An array with two dimensions is called as a two-dimensional array. It is also called as a matrix. In C, a two dimensional array is initialized as int arr[nb_of_rows] [nb_of_columns]. Hence, two dimensional arrays can be considered as a grid. An element in a two dimensional can be accessed by mentioning its row and column. If the array has 20 integer values, it will occupy 80 bytes in memory (assuming 4 bytes for an integer). All of the bytes are in consecutive memory locations, the first row occupying the first 20 bytes, the second the next 20, and so on.

3. Explain Array of pointers?

An array of pointers is an array consisting of pointers. Here, each pointer points to a row of the matrix or an element. E.g char *array [] = {“a”, “b”}. This is an array of pointers to to characters.

4. What is keyed array data structure?

A "Keyed Array Data Structure" is an array data structure with one subfield identified as the search or sort key. The array data structure is indexed by (*) and followed by the specification of the key subfield. For example, consider array data structure FAMILIES with one scalar subfield NAME, and another array subfield CHILDREN. To use the FAMILIES data structure as an array data structure keyed by NAME, specify FAMILIES(*).NAME. To use the first CHILDREN element as the key, specify FAMILIES(*).CHILDREN(1).

5. Explain array data structure?

An Array Data Structure is a data structure defined with keyword DIM. An array data structure is like a multiple-occurrence data structure, except that the index is explicitly specified, as with arrays.

6. What is data structure subfields?

You define a subfield by specifying blanks in the Definition-Type entry of a definition specification. The subfield definition(s) must immediately follow the data structure definition. The subfield definitions end when a definition specification with a non-blank Definition-Type entry is encountered, or when a different specification type is encountered.

7. What will be output if you will execute following c code?
#include<stdio.h>
void main(){
char arr[7]="Network";
printf("%s",arr);

Garbage value.

8. What will be output if you will execute following c code?
#include<stdio.h>
void main(){
char arr[11]="The African Queen";
printf("%s",arr);

null.

9. What will be output if you will execute following c code?
#include<stdio.h>
void main(){
char arr[20]="MysticRiver";
printf("%d",sizeof(arr));

20

10. What will be output if you will execute following c code?
#include<stdio.h>
void main(){
int const SIZE=5;
int expr;
double value[SIZE]={2.0,4.0,6.0,8.0,10.0};
expr=1|2|3|4;
printf("%f",value[expr]);

Compilation error

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11. What will be output if you will execute following c code?
#include<stdio.h>
enum power{
Dalai,
Vladimir=3,
Barack,
Hillary
};
void main(){
float leader[Dalai+Hillary]={1.f,2.f,3.f,4.f,5.f};
enum power p=Barack;
printf("%0.f",leader[p>>1+1]);

2

12. What will be output if you will execute following c code?
#include<stdio.h>
#define var 3
void main(){
char *cricket[var+~0]={"clarke","kallis"};
char *ptr=cricket[1+~0];
printf("%c",*++ptr);

l

13. What will be output if you will execute following c code?
#include<stdio.h>
#define var 3
void main(){
char data[2][3][2]={0,1,2,3,4,5,6,7,8,9,10,11};
printf("%o",data[0][2][1]);

5

14. What will be output if you will execute following c code?
#include<stdio.h>
#define var 3
void main(){
short num[3][2]={3,6,9,12,15,18};
printf("%d %d",*(num+1)[1],**(num+2));

15 15

15. What will be output if you will execute following c code?
#include<stdio.h>
#define var 3
void main(){
char *ptr="cquestionbank";
printf("%d",-3[ptr]);

-101

16. What will be output if you will execute following c code?
#include<stdio.h>
void main(){
long myarr[2][4]={0l,1l,2l,3l,4l,5l,6l,7l};
printf("%ldt",myarr[1][2]);
printf("%ld%ldt",*(myarr[1]+3),3[myarr[1]]);
printf("%ld%ld%ldt" ,*(*(myarr+1)+2),*(1[myarr]+2),3[1[myarr]]);

6 77 667

17. What will be output if you will execute following c code?
#include<stdio.h>
void main(){
int array[2][3]={5,10,15,20,25,30};
int (*ptr)[2][3]=&array;
printf("%dt",***ptr);
printf("%dt",***(ptr+1));
printf("%dt",**(*ptr+1));
printf("%dt",*(*(*ptr+1)+2));

5 Garbage value 20 30

18. What will be output if you will execute following c code?
#include<stdio.h>
void main(){
static int a=2,b=4,c=8;
static int *arr1[2]={&a,&b};
static int *arr2[2]={&b,&c};
int* (*arr[2])[2]={&arr1,&arr2};
printf("%d %dt",*(*arr[0])[1], *(*(**(arr+1)+1)));

4 8

19. What will be output if you will execute following c code?
#include<stdio.h>
#include<math.h>
double myfun(double);
void main(){
double(*array[3])(double);
array[0]=exp;
array[1]=sqrt;
array[2]=myfun; printf("%.1ft",(*array)((*array[2])((**(array+1))(4))));

}
double myfun(double d){
d-=1;
return d;
}

2.7

20. What will be output if you will execute following c code?
#include<stdio.h>
#include<math.h>
typedef struct{
char *name;
double salary;
}job;
void main(){
static job a={"TCS",15000.0};
static job b={"IBM",25000.0};
static job c={"Google",35000.0};
int x=5;
job * arr[3]={&a,&b,&c};
printf("%s %ft",(3,x>>5-4)[*arr]);
}
double myfun(double d){
d-=1;
return d;

Google 35000.000000

21. What will be output if you will execute following c code?
#include<stdio.h>
union group{
char xarr[2][2];
char yarr[4];
};
void main(){
union group x={'A','B','C','D'};
printf("%c",x.xarr[x.yarr[2]-67][x.yarr[3]-67]);
}

B

22. What will be output if you will execute following c code?
#include<stdio.h>
void main(){
int a=5,b=10,c=15;
int *arr[3]={&a,&b,&c};
printf("%d",*arr[*arr[1]-8]);

Compilation error

23. What will be output if you will execute following c code?
#include<stdio.h>
void main(){
int arr[][3]={{1,2},{3,4,5},{5}};
printf("%d %d %d",sizeof(arr),arr[0][2],arr[1][2]);
}

18 0 5

24. What will be output if you will execute following c code?
#include<stdio.h>
void main(){
int xxx[10]={5};
printf("%d %d",xxx[1],xxx[9]);

0 0

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25. What will be output if you will execute following c code?
#include<stdio.h>
#define WWW -1
enum {cat,rat};
void main(){
int Dhoni[]={2,'b',0x3,01001,'x1d','111',rat,WWW};
int i;
for(i=0;i<8;i++)
printf(" %d",Dhoni[i]);

2 98 3 513 29 73 1 -1