fig06_18.c

C程序设计经典教程第5版程序示例,比较适合初级c语言的学生

/* Fig. 6.18: fig06_18.c
   Linear search of an array */
#include <stdio.h>
#define SIZE 100

/* function prototype */
int linearSearch( const int array[], int key, int size ); 

/* function main begins program execution */
int main( void )
{   
   int a[ SIZE ]; /* create array a */
   int x; /* counter for initializing elements 0-99 of array a */
   int searchKey; /* value to locate in array a */
   int element; /* variable to hold location of searchKey or -1 */

   /* create data */
   for ( x = 0; x < SIZE; x++ ) { 
      a[ x ] = 2 * x;
   } /* end for */

   printf( "Enter integer search key:\n" );
   scanf( "%d", &searchKey );

   /* attempt to locate searchKey in array a */
   element = linearSearch( a, searchKey, SIZE );

   /* display results */
   if ( element != -1 ) {
      printf( "Found value in element %d\n", element );
   } /* end if */
   else {
      printf( "Value not found\n" );
   } /* end else */

   return 0; /* indicates successful termination */

} /* end main */

/* compare key to every element of array until the location is found
   or until the end of array is reached; return subscript of element
   if key or -1 if key is not found */
int linearSearch( const int array[], int key, int size )
{
   int n; /* counter */

   /* loop through array */
   for ( n = 0; n < size; ++n ) {

      if ( array[ n ] == key ) { 
         return n; /* return location of key */
      } /* end if */

   } /* end for */

   return -1; /* key not found */

} /* end function linearSearch */



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