/*

Demonstration of linear search algorithm used to find

for the search is the student's I.D. number.

*/

#include<stdio.h>

#include<stdlib.h>

#define MAXSTUDENTS 50 /* Constant */

/* linear Function Declaration */

int linear(long int id[], long int key, int n)

{

/*

Simple linear search - check all the elements of the

array for a match starting at zero until a match is found.

On average, the function will make n/2 comparisons.

If no match is found, a not-found flag is returned, otherwise

the function returns the correct subscript for the student record

*/

int i, flag;

flag = -1;

for( i=0; i<n; i++){

if( id[i] == key ){

flag = i;

break;

}

}

return(flag);

}

main()

{

/* Declaration Statements */

char names[MAXSTUDENTS][25];

int i, n, flag, cont, yes_no;

long int id[MAXSTUDENTS], key;

/* Enter data */

do{

printf("How many students? (<%4d)",MAXSTUDENTS);

scanf("%d",&n);

}while( n>MAXSTUDENTS );

printf("in this format ->Name:Doe,John[ENTER] (no spaces)\n");

printf(" ->ID #:9421234[ENTER]\n");

for( i=0; i<n; i++){

printf("Student #%d:\n",i+1);

printf("Name: ");

scanf("%s",names[i]);

printf("ID #: ");

scanf("%ld",&id[i]);

}

printf("\n\n\nDemonstration of linear search\n\n");

do{ /* Keep on looking up names until user wants to quit */

printf("Enter search key (ID#)\n");

scanf("%ld",&key);

printf("\n **SEARCHING**\n");

flag = linear(id, key, n);

/* flag will equal -1 if no match was found, or the correct

array subscript for the student */

cont = 0;

if(flag == -1){

scanf("%d",&yes_no);

}

else {

printf(" **FOUND**\n");

printf("Name:%s ID #:%ld\n\n", names[flag], id[flag]);

printf("Look up another student (0 for no, 1 for yes)? ");

scanf("%d",&yes_no);

}

}while(yes_no == 1);

}

/* End of main program linear.c */

/*

Input :

8

Milo,Bloom 9611684

Cat,theBill 9613986

Dallas,Steven 9412978

Cutter,John 9613693

Jones,Oliver 9515010

Binkley,Mike 9510633

Opus,Holland 9513221

Dummy,One 0000000

Output :

How many students? (< 50)Enter students' names and grades

in this format ->Name:Doe,John[ENTER] (no spaces)

->ID #:9421234[ENTER]

Student #1:

Name:Milo,Bloom

ID #:9611684

Student #2:

Name:Cat,theBill

ID #:9613986

Student #3:

Name:Dallas,Steven

ID #:9412978

Student #4:

Name:Cutter,John

ID #:9613693

Student #5:

Name:Jones,Oliver

ID #:9515010

Student #6:

Name:Binkley,Mike

ID #:9510633

Student #7:

Name:Opus,Holland

ID #:9513221

Student #8:

Name:Dummy,One

ID #:0000000

Demonstration of linear search

Enter search key (ID#)

9611684

**SEARCHING**

**FOUND**

Name:Milo,Bloom ID #:9611684

Look up another student (0 for no, 1 for yes)?0

*/