Array tutorials in c programming language by examples
An array is derived data type in c programming language which
can store similar type of data in continuous memory location.
Data may be primitive type (int, char, float, double…), address of
union, structure, pointer, function or another array.
Example of array declaration:
int arr[5];
char arr[5];
float arr[5];
long double arr[5];
char * arr[5];
int (arr[])();
double ** arr[5];
Array is useful when:
(a) We have to store large number of data of similar type. If we
have large number of similar kind of variable then it is very
difficult to remember name of all variables and write the
program. For example:
//PROCESS ONE
#include<stdio.h>
int main(){
int ax=1;
int b=2;
int cg=5;
int dff=7;
int am=8;
int raja=0;
int rani=11;
int xxx=5;
int yyy=90;
int p;
int q;
int r;
int avg;
avg=(ax+b+cg+dff+am+raja+rani+xxx+yyy+p+q+r)/12;
printf("%d",avg);
return 0;
}
If we will use array then above program can be written as:
//PROCESS TWO
#include<stdio.h>
int main(){
int arr[]={1,2,5,7,8,0,11,5,50};
int i,avg;
for(int i=0;i<12;i++){
avg=avg+arr[i];
}
printf("%d",avg/12);
return 0;
}
Question: Write a C program to find out average of 200 integer
number using process one and two.
(b) We want to store large number of data in continuous memory
location. Array always stores data in continuous memory location.
(q) What will be output when you will execute the following
program?
#include<stdio.h>
int main(){
int arr[]={0,10,20,30,40};
char *ptr=arr;
arr=arr+2;
printf("%d",*arr);
return 0;
}
Advantage of using array:
1. An array provides singe name .So it easy to remember the
name of all element of an array.
2. Array name gives base address of an array .So with the help
increment operator we can visit one by one all the element of an
array.
3. Array has many application data structure.
Array of pointers in c:
Array whose content is address of another variable is known
as array pointers. For example:
#include<stdio.h>
int main(){
float a=0.0f,b=1.0f,c=2.0f;
float * arr[]={&a,&b,&c};
b=a+c;
printf("%f",arr[1]);
return 0;
}
Complex arrays in c
1. Declaration of an array of size five which can store address
such functions whose parameter is void data type and return type
is also void data type:
void ( arr[5] )( );
2. Declaration of an array of size five which can store address
such function which has two parameter of int data type and
return type is float data type:
float ( arr[5] )(int, int);
3. Declaration of an array of size two which can store the address
of printf or sacanf function:
int ( arr[2] )( const char *, … );
Note: prototype of printf function is: int printf( const char *, … );
Different type of array in c:
(a) Array of integer
An array which can hold integer data type is known as array of
integer.
(b) Array of character
An array which can hold character data type is known as array
of character.
(c) Array of union
An array which can hold address of union data type is known as
union of integer.
For example:
(1) What will be output when you will execute the following
program?
#include<stdio.h>
union A{
char p;
float const * const q;
};
int main(){
union A arr[10];
printf("%d",sizeof arr);
return 0;
}
Output: 20
(2) What will be output when you will execute the following
program?
#include<stdio.h>
union A{
char character;
int ascii;
};
int main(){
union A arr[2]={{65},{'a'}};
printf("%c %c",arr[0],arr[1]);
return 0;
}
Output: A a
(d) Array of structure
An array which can hold address of structure data type is known
as array of structure. For example:
(1) What will be output when you will execute the following
program?
#include<stdio.h>
typedef struct stu{
char * name;
int roll;
}s;
int main(){
s arr[2]={{"raja",10},{"rani",11}};
printf("%s %d",arr[0]);
return 0;
}
Output: raja 10
(2) What will be output when you will execute the following
program?
#include<stdio.h>
struct A{
int p;
float q;
long double *r;
};
int main(){
struct A arr[10];
printf("%d",sizeof arr);
return 0;
}
Output: 80
(e) Array of string
An array which can hold integer data type is known as array of
integer.
(f) Array of array
An array which can hold address of another array is known as
array of array.
(g) Array of address of integer
An array which can hold address integer data type is known as
array of address of integer.
Pointer to array
A pointer which holds base address of an array or address of any
element of an array is known as pointer to array. For example:
(a)
#include<stdio.h>
int main(){
int arr[5]={100,200,300};
int *ptr1=arr;
char *ptr2=(char *)arr;
printf("%d %d",*(ptr1+2),*(ptr2+4));
return 0;
}
Output: 300 44
(b)
#include<stdio.h>
int main(){
static int a=11,b=22,c=33;
int * arr[5]={&a,&b,&c};
int const * const *ptr=&arr[1];
--ptr;
printf("%d ",**ptr);
return 0;
}
Output: 11
