Flowchart of Sequential Searches and script in c

Remarks

• A sequential search starts at the bginning of the list, and checks each item in the list until it finds a match or until it reaches the end of the list. 
• A sequential search has one loops, which iterates to the size of the list.  This makes the algorithm O(n); that is, maximum execution time is proportional to the list length. 
• If the list doubles in length, average execution time is multiplied by 2. 
• A sequential search is acceptable for short lists, but for long lists, there are better searching algorithms. 

Example

/*************************************************
 * File:         SequentialSearch.cpp
 * Description:  A short program using 
 *               sequential search
 * Date:         11/3/08
 *************************************************/

#include <iostream>
#include <cmath>
#include <cstring>
using namespace std;

//

void Display (int List[], int Size);
//Precondition:
//  List is an array of at least Size integers
//Postcondition:
//  The first Size integers in the List 
//  are displayed, separated by blanks.
//
char * Ordinal (int Index, char * Text);
//Precondition:
//  Index is a non-negative integer
//  Text is a character string long enough to hold the result
//Postcondition:
//  Text and the return value is the ordinal string
//  corresponding to the index: e.g., 0 => 1st, 5 => 6th
//
void Populate (int List[], int Size);
//Precondition:
//  List is an array of at least Size integers
//Postcondition:
//  The first Size integers in the List 
//  are populated with random integers
//
int SequentialSearch (int Goal, int List[], int Size);
//Precondition:
//  List is an array of at least Size integers
//Postcondition:
//  If Goal is in the list, the return value is the
//  location (0..Size-1)of Goal in the list.
//  If Goal is not in the list, the return value is -1
//
int main () {
  const int SIZE = 10;
  int Items [SIZE];
  int Goal;
  int Location;
  char Ord [16];
  char Response;
  
  cout << "Sequential Search Example\n";
  Populate (Items, SIZE);
  cout << "The List:\n";
  Display (Items, SIZE);
  do {
    cout << "Number to search for?  ";
    cin >> Goal;
    Location = Search (Goal, Items, SIZE);
    if (Location < 0) {
      cout << Goal << " is not in the list.\n";
    } else {
      cout << Goal << " is in the " 
           << Ordinal (Location, Ord) << " Location " << endl;
    }
    cout << "Do you want to search again (Y/N)?  ";
    cin >> Response;
  } while (toupper (Response) == 'Y');
  
  return 0;
}
//
void Display (int List[], int Size) {
  int i;
  i = 0;
  while (i < Size) {
    cout << List [i] << ' ';
    ++i;
  }
  cout << endl;
}
//
char * Ordinal (int i, char * Ord) {
  static const char * Suffix [] =
    {"st", "nd", "rd", "th", "th", "th", "th", "th", "th", "th"};
  sprintf (Ord, "%d", i + 1);
  strcat (Ord, Suffix [i % 10]);
  return Ord;    
}
//
void Populate (int List[], int Size) {
  int i;
  i = 0;
  randomize ();
  while (i < Size) {
    List [i] = 1 + rand() % 99;
    ++i;
  }
}
//
int SequentialSearch (int Goal, int List[], int Size) {
  int i;
  i = 0;
  while ((i < Size) && (List [i] != Goal)) {
    ++i;
  }
  if (i == Size) {
    i = -1;
  }
  return i;
}
//
Output
Sequential Search Example
The List:
11 8 39 1 2 1 12 40 80 62 
Number to search for?  44
44 is not in the list.
Do you want to search again (Y/N)?  y
Number to search for?  11
11 is in the 1st Location 
Do you want to search again (Y/N)?  n