ARRAYS IN C

Written by Kousik :

C provides some fundamental DATA types. They are int, float, char, double. They are very useful and important in C language. But they have a limiting fact. The fact is that a variable of these types can store only one value at a time. With variables of those types we cannot handle a large volume of data of same type at a time. So we need a powerful data type with which we can solve this problem. C supports such a data type called ARRAYS.

Definition: An array is a well defined collection of elements of same data type. In others words One can say that an array is grouping of some elements that are of same data type. Some applications of arrays in C are given below:

§  To store age of some boys.

§  To store marks of subjects.

§  To store daily rainfall data.

And so on.

Declaration of ARRAYS:  ARRAY in C can be declared by following format

int array[50]; , float temperature[7];

See carefully that an array is declared by defining the data type first then the name and then the  size of array.

Now a question should be come to reader’s mind and that is how can we take input of many elements at a time by using array? Answer of this question is very easy. This problem can be solved by using for loop for taking input by using following syntax.

For (i=0; i<n; i++)

Scanf (“%d”, &arr[i]);

Where n is the size of the array and arr is the name of array.

Now here a example is given to understand ARRAYS and the way of using an ARRAY in C.

#include<stdio.h>
int main()
{
int a[25],i,n,sum=0,mean;
printf("Enter the number of array elements\n");
scanf("%d",&n);
printf("Enter the value of array elements\n");
for(i=0;i<n;i++)
{
scanf("%d",&a[i]);
}
for(i=0;i<n;i++)
{
Printf(“%d ”, a[i]);
}
return 0;
}

There are two kinds of array those can be used in C language. One is ONE DIMENSIONAL and the other one is TWO DIMENSIONAL.

In this section we will discuss about only one dimensional array.

INITIALIZATION OF ONE DIMENSIONAL ARRAY: After declaring an array its elements can be initialized. Otherwise elements of array are of ‘garbage’. The following syntax can be used to initialize an array.

Data type  variablename[size]={values};

Example : int student[3]={1,2,3};

Above example is called compile time initialization. Another type of initialization can be used for initialize an array. That is Run time initialization. For example take the following segment.

  for(j=0;j<50;j++)

  {

    If(j<20)

   A[i]=0.0;

   Else

   A[i]=1.0;

  }

 We can also use a scanf function to initialize an array as we discuss earlier with the answer of the question how to take input value of elements of an array.

The following example illustrates a sorting program in ascending order as an important application of arrays in C science.

/* a program to sort an array */
# include<stdio.h>
int main()
{
int a[25],i,j,n,temp,item;
char c;
printf("Enter the number of array elements\n");
scanf("%d",&n);
printf("Enter the value of array elements\n");
for(i=0;i<n;i++)
{
scanf("%d",&a[i]);
}
/* sorting of array */
for(i=0;i<n;i++)
{
for(j=i+1;j<n;j++)
{
if(a[i]>a[j])
{
temp=a[i];
a[i]=a[j];
a[j]=temp;
}
}
}
printf("After sorting \n");
for(i=0;i<n;i++)
{
printf("%d ",a[i]);
}
}