C++ Tutorial/Array/array

array of strings

<source lang="cpp">#include <iostream>

 using namespace std;  
   
 int main(){  
    const int DAYS = 7;           
    const int MAX = 10;           
    char star[DAYS][MAX] = { "Sunday", "Monday", "Tuesday",  
                             "Wednesday", "Thursday",  
                             "Friday", "Saturday"  };  
    for(int j=0; j<DAYS; j++) 
       cout << star[j] << endl;  
    return 0;  
   }</source>

Initializing an array

<source lang="cpp">#include <iostream> using std::cout; using std::endl;

1. include <iomanip>

using std::setw; int main() {

  int n[ 10 ];
  for ( int i = 0; i < 10; i++ )        
     n[ i ] = 0;
  for ( int j = 0; j < 10; j++ )        
     cout << n[ j ] << endl;
  return 0;

}</source>

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Initializing an array in a declaration.

<source lang="cpp">#include <iostream> using std::cout; using std::endl;

1. include <iomanip>

using std::setw; int main() {

  int n[ 10 ] = { 2, 7, 4, 8, 5, 4, 9, 7, 6, 3 };
  
  for ( int i = 0; i < 10; i++ )
     cout << n[ i ] << endl;
  return 0;

}</source>

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Linear search of an array

<source lang="cpp">#include <iostream> using std::cout; using std::cin; using std::endl; int linearSearch( const int [], int, int ); // prototype int main() {

  const int arraySize = 100;
  int a[ arraySize ];
  int searchKey = 28;
  for ( int i = 0; i < arraySize; i++ ) 
     a[ i ] = 2 * i;
  int element = linearSearch( a, searchKey, arraySize );
  cout << element << endl;
  return 0;

} int linearSearch( const int array[], int key, int sizeOfArray ) {

  for ( int j = 0; j < sizeOfArray; j++ ){
     if ( array[ j ] == key ){
        return j;
     }
  }
  return -1;

}</source>

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Obtaining the number of array elements

<source lang="cpp">#include <iostream> using std::cout; using std::endl; int main() {

 int values[] = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29};
 cout << endl
      << "There are "
      << sizeof values/sizeof values[0]
      << " elements in the array."
      << endl;
 return 0;

}</source>

There are 10 elements in the array.

Passing arrays and individual array elements to functions

<source lang="cpp">#include <iostream> using std::cout; using std::endl;

1. include <iomanip>

using std::setw; void modifyArray( int [], int ); // appears strange void modifyElement( int ); int main() {

  const int arraySize = 5; // size of array a
  int a[ arraySize ] = { 0, 1, 2, 3, 4 }; // initialize array a
  modifyArray( a, arraySize );  
  for ( int i = 0; i < arraySize; i++ )
     cout << setw( 3 ) << a[ i ];
  modifyElement( a[ 3 ] );
  cout << a[ 3 ] << endl;
  return 0;

} void modifyArray( int b[], int sizeOfArray ) {

  for ( int i = 0; i < sizeOfArray; i++ )
     b[ i ] = 200;

} void modifyElement( int e ) {

  e = 200 ;

}</source>

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Static arrays are initialized to zero.

<source lang="cpp">#include <iostream> using std::cout; using std::endl; void staticArrayInit( void ); void automaticArrayInit( void ); int main() {

  staticArrayInit();
  automaticArrayInit();
  staticArrayInit();
  automaticArrayInit();
  return 0;

} void staticArrayInit( void ) {

  static int array1[ 3 ];
  for ( int i = 0; i < 3; i++ )
     cout << "array1[" << i << "] = " << array1[ i ] << "  ";
  for ( int j = 0; j < 3; j++ )
     array1[ j ] = 0;

} void automaticArrayInit( void ) {

  int array2[ 3 ] = { 1, 2, 3 };
  for ( int i = 0; i < 3; i++ )
     cout << "array2[" << i << "] = " << array2[ i ] << "  ";
  for ( int j = 0; j < 3; j++ )
     array2[ j ] = 0;

}</source>

array1[0] = 0  array1[1] = 0  array1[2] = 0  array2[0] = 1  array2[1] = 2  array
2[2] = 3  array1[0] = 0  array1[1] = 0  array1[2] = 0  array2[0] = 1  array2[1]
= 2  array2[2] = 3

Use subscripting and pointer notations with arrays

<source lang="cpp">#include <iostream> using std::cout; using std::endl; int main() {

  int b[] = { 10, 20, 30, 40 };
  int *bPtr = b;
  for ( int i = 0; i < 4; i++ )
     cout << *( b + i ) << "\n";
  for ( int j = 0; j < 4; j++ )
     cout << bPtr[ j ] << "\n";
  for ( int i = 0; i < 4; i++ )
     cout << *( bPtr + i ) << "\n";
  return 0;

}</source>

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