C Tutorial/Array/Array Search — различия между версиями

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(нет различий)

Версия 14:21, 25 мая 2010

Binary search of an array

#include <stdio.h>
#define SIZE 15
int binarySearch( const int b[], int searchKey, int low, int high );
int main() {
   int a[ SIZE ];
   int i;
   int key = 10;
   int result = -1;
   for ( i = 0; i < SIZE; i++ ) {
      a[ i ] = 2 * i;
   }
   result = binarySearch( a, key, 0, SIZE - 1 );
   if ( result != -1 ) {
      printf( "\n%d found in array element %d\n", key, result );
   } else {
      printf( "\n%d not found\n", key );
   }
   return 0;
}
int binarySearch( const int b[], int searchKey, int low, int high )
{
   int middle;
   while ( low <= high ) {
      middle = ( low + high ) / 2;
      if ( searchKey == b[ middle ] ) {
         return middle;
      } else if ( searchKey < b[ middle ] ) {
         high = middle - 1;
      } else {
         low = middle + 1;
      }
   }
   return -1;
}
10 found in array element 5

Linear search of an array

#include <stdio.h>

#define SIZE 100
int linearSearch( const int array[], int key, int size ); 
int main()
{   
   int a[ SIZE ]; 
   int x; 
   int searchKey; 
   int element; 
   for ( x = 0; x < SIZE; x++ ) { 
      a[ x ] = 2 * x;
   } 
   printf( "Enter integer search key:\n" );
   scanf( "%d", &searchKey );
   element = linearSearch( a, searchKey, SIZE );
   if ( element != -1 ) {
      printf( "Found value in element %d\n", element );
   } 
   else {
      printf( "Value not found\n" );
   } 
   return 0;
}
int linearSearch( const int array[], int key, int size )
{
   int n;
   for ( n = 0; n < size; ++n ) {
      if ( array[ n ] == key ) { 
         return n;
      } 
   } 
   return -1;
}
Enter integer search key:
2
Found value in element 1