1.Single dimensional array
Array having only one dimentional is called as single dimensional array
Syntax–
Var_name=new Data_type[size];
Example
a=new int[5];
First we have declared a variable having unknown size and then size is defined with using new operator and memory is allocated
Let’s execute program of single dimensional array
Problem– Calculate sum of five integer number using array
Code–>>
public static void main(String args[])
{
int a[ ];
a=new int[5];
for(int j=0;j<5;j++)
{
a[j]=j;
}
int result=0;
for(int i=0;i<5;i++)
{
result=result+a[i];
}
System.out.println(“Sum of values =”+result);
}
}
output–>>
Sum of values= 10
Logic–>>
First we have declared an array variable ‘a’ and defined it’s size with new operator .Now we initialized its five value with using for loop .So first a[o]=0 ,a[1]=1…and so on.
Then we have taken a variable result having integer type and initialized it’s value to zero.Now inside for loop we have written operation to calculate sum.In First iteration result will be 0,in second it become 1,in third it become 3 …and in last it become 10.So it finally prints the result= 10.
2.Multidimensional array-It have two or more dimension having same data type and same name.
Syntax
Var_name= new Data_type [size][size];
Example
a=new int [3][3];
It have two dimensions and size of two dimensions is generated.
Let’s execute multi-dimensional array program in java
Problem-Execute a java program to print matrix.
Code–>>
public static void main(String args[])
{
int a[][];
a=new int[3][3];
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++)
{
a[i][j]=j;
}
}
System.out.println(“Matrix is “);
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++)
{
System.out.print(” “+a[i][j]);
}
System.out.println(” “);
}
}
}
Output–>>
0 1 2
0 1 2
0 1 2
Logic–>>
It is easy to print matrix with using multidimensional array .First we have declared variable having two dimension and initialized it’s index with value using two for loop statement.When i is equal to zero it goes inside the loop and execute the statement until j become 3.So it have a[0][0]=0,a[0][1]=1 and a[0][2]=2. Similarly we can do it for i=1 and i=2.After initializing its value to particular index,we will do same process for printing it into matrix form.Note that we used print instead of println inside the for loop with j variable.