1-D Array
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| 1-D Array in C++ |
- An array is a collection of data elements of same data type.
- It is described by a single name and each element of an array is referenced by using array name and its subscript no.
Declaration of Array
Type arrayName[numberOfElements];
For example,
int Age[5] ;
float cost[30];
Initialization of One Dimensional Array
- An array can be initialized along with declaration. For array initialization it is required to place the elements separated by commas enclosed within braces.
int A[5] = {11,2,23,4,15};
- It is possible to leave the array size open. The compiler will count the array size.
int B[] = {6,7,8,9,15,12};
Referring to Array Elements
In any point of a program in which an array is visible, we can access the value of any of its elements individually as if it was a normal variable, thus being able to both read and modify its value. The format is as simple as:
name[index]
Examples:
cout<<age[4]; //print an array element
age[4]=55; // assign value to an array element
cin>>age[4]; //input element 4
Using Loop to input an Array from user
int age [10], i ;
for (i=0 ; i<10; i++)
{
cin>>age[i];
}
Arrays as Parameters
- At some moment we may need to pass an array to a function as a parameter.
- In C++ it is not possible to pass a complete block of memory by value as a parameter to a function, but we are allowed to pass its address.
For example, the following function:
void print(int A[])
accepts a parameter of type "array of int" called A.
In order to pass to this function an array declared as:
int arr[20];
we need to write a call like this:
print(arr);
Here is a complete example:
#include <iostream.h>
void print(int A[], int length)
{
for (int n=0; n<length; n++)
cout << A[n] << " ";
cout << "\n";
}
int main ()
{
int arr[] = {5, 10, 15};
print(arr,3);
return 0;
}
Basic Operation On One Dimensional Array
Function to traverse the array A
void display(int A[], int n)
{
cout<<"The elements of the array are:\n";
for(int i=0;i<n;i++)
cout<<A[i];
}
Function to Read elements of the array A
void Input(int A[], int n)
{
cout<<"Enter the elements:";
for(int i=0;i<n;i++)
cin>>A[i];
}
Function to Search for an element from A by Linear Search
void lsearch(int A[], int n, int data)
{
int i;
for(i=0; i<n; i++)
{
if(A[i]==data)
{
cout<<"Data Found at : "<<i;
return;
}
}
cout<<"Data Not Found in the array"<<endl;
}
Function to Search for an element from Array A by Binary Search
int BsearchAsc(int A[], int n, int data)
{
int Mid,Lbound=0,Ubound=n-1,Found=0;
while((Lbound<=Ubound) && !(Found))
{
Mid=(Lbound+Ubound)/2; //Searching The Item
if(data>A[Mid])
Lbound=Mid+1;
else if(data<A[Mid])
Ubound=Mid-1;
else
Found++;
}
if(Found)
return(Mid+1); //returning 1ocation, if present
else
return(-1); //returning -1,if not present
}
Function to Sort the array A by Bubble Sort
void BSort(int A[], int n)
{
int I,J,Temp;
for(I=0;I<n-1;I++) //sorting
{
for(J=0;J<(n-1-I);J++)
if(A[J]>A[J+1])
{
Temp=A[J]; //swapping
A[J]=A[J+1];
A[J+1]=Temp;
}
}
}
Function to Sort the array ARR by Insertion Sort
void ISort(int A[], int n)
{
int I,J,Temp;
for(I=1;I<n;I++) //sorting
{
Temp=A[I];
J=I-1;
while((Temp<A[J]) && (J>=0))
{
A[J+1]=A[J];
J--;
}
A[J+1]=Temp;
}
}
Function to Sort the array by Selection Sort
void SSort(int A[], int n)
{
int I,J,Temp,Small;
for(I=0;I<n-1;I++)
{
Small=I;
for(J=I+1;J<n;J++) //finding the smallest element
if(A[J]<A[Small])
Small=J;
if(Small!=I)
{
Temp=A[I]; //Swapping
A[I]=A[Small];
A[Small]=Temp;
}
}
}
Function to merge A and B arrays of lenghts N and M
void Merge(int A[], int B[], int C[], int N, int M, int &K)
{
int I=0, J=0;
K=0; //Initialisation of counters for A, B, and C
while (I<N && J<M)
{
if (A[I]<B[J])
C[K++]=A[I++];
else if (A[I]>B[J])
C[K++]=B[J++];
else
{
C[K++]=A[I++];
J++;
}
}
for (int T=I;T<N;T++)
C[K++]=A[T];
for (T=J;T<M;T++)
C[K++]=B[T];
}