declare arrays:
arraytype arrayName[arraySize]; //basic syntax
example:
int zakiLive[10];
Initialize arrays:
int zakiLive[5]={4,5,6,8};
zakiLive[3]=8
It means value 8 is in 3rd index in array zakiLive as index in array count from 0 and it goes on..
Here is an example of array
#include<iostream>
using namespace std;
#include<iomanip>
using std::setw;
int main(){
int n[10]; //n is an array of 10 integers
for(int i=0;i<10;i++){
n[i]=i+100;
}
cout<<"Element"<<setw(15)<<"Value"<<endl; //here setw() built in library function is using to make a gap between Element and Value
//output
for(int j=0;j<10;j++){
cout<<setw(2)<<j<<setw(19)<<n[j]<<endl;
}
return 0;
}
C++ Arrays have some types:
Multi-Dimensional Arrays:
syntax can be like this
array_data_type array_name[size1][size2][size3]……..[sizeN];
Two Dimensional Arrays(It is one kind of multidimensional arrays):
type arrayName[x][y];
Initialize Two Dimensional Arrays:
int a[3][4]={
{0,1,2,3},
{4,5,6,7},
{8,9,10,11}
};
We can also write equivalent like this
int a[3][4]={0,1,2,3,4,5,6,7,8,9,10,11};
We can accesss Two-Dimensional Array elemets by
int valueArray=a[2][3];
Here is a code
#include<iostream>
using namespace std;
int main()
{
//declaring an array with 5 rows and 2coloumns
int a[5][2]={
{0,0},
{1,2},
{2,4},
{3,6},
{4,8},
};
//output
for(int i=0;i<5;i++){
for(int j=0;j<2;j++){
cout<<"a["<<i<<"]"<<"["<<j<<"] : ";
cout<<a[i][j]<<endl;
}
}
return 0;
}
C++ Pointer to an Array
#include<iostream>
using namespace std;
int main(){
double balance[5]={100.09,2.8,3.4,17.8,8.8};
double *p;
p=balance;
//output eache array elements value by pointer p
cout<<"endl";
cout<<"Array values using pointer"<<endl<<endl;
for(int i=0;i<5;i++){
cout<<"*(p+"<<i<<"): ";
cout<< *(p+i) <<endl;
}
//the output means it is pointing to the array balance by *p to p=balance;
//now the bvalance will give some other output also
cout<<"Array values using balance as address"<<endl<<endl;
for(int i=0/* we are giving here 0 as any array starts from 0*/;i<5;i++){
cout<<"*(balance+"<<i<<" )";
cout<<*(balance+i)<<endl;
}
return 0;
}
Here it is happeing like this shown above.
There are another 2 types of C++ array functioning with pointer
Passing Arrays to Function and Returning Array From Functions
Now let discuss in details
Passing Arrays to Function:
What we know from the function synatx is
function_type function_name(arguments_type arguments_name,arguments_type arguments_name){
function_body;
return function_type;
}
But it’s not possible to pass a full array to the argument by using an index number..But we can pass an array by using without an index..This process can be done by three steps
Way-1
Formal Parameters as a pointer
void myFunction(int *param)
{
//Statements
}
Way-2
Formal Parameters as a size array as follows
void myFunction(int param[10])
{
//statements
}
Way-3
Formal Paramaeters as an unsized array as follows
void myFunction(int param[])
{
//statements
}
The example given here with array without size
#include<iostream>
using namespace std;
double getAverage(int arr[],int sizes);
int main(){
int balance[5]={1000, 2, 3, 17, 50};
double avg;
//passing pointer to the array as an argument.
avg=getAverage(balance,5);
//output the returned value
cout<<"Average value is : "<<avg<<endl;
return 0;
}
double getAverage(int arr[], int sizes)
{
int i,sum=0;
double avg;
for(i=0;i<sizes;++i)
{
sum+=arr[i];
}
avg=double(sum)/sizes;
return avg;
}
Return Array from Functions:
#include<iostream>
#include<ctime>
using namespace std;
int *getRandom()
{
static int r[10];
//set the seed for random numbers
srand( (unsigned)time( NULL ) );
for(int i=0;i<10;++i)
{
r[i]=rand();
cout<<r[i]<<endl;
}
return r;
}
int main()
{
int *p;
p=getRandom();
// a pointer to an int
for(int i=0;i<10;i++){
cout<<"(p+"<<i<<") :";
cout<<*(p+i)<<endl;
}
return 0;
}
We will discss this later more In Sha Allah 🙂
