Thread: Simple search program

Hi Guys,

I have a tutorial question that ask that I make a program to hold students names and grades.

I must be able to search by name or ID number.

I have the programe running except the search by name, if there is more than 1 record with the same name i get a general protection fault adn the program crashes, if there is just 1 name in the records the search works fine.

I wonder of someone could look at my function "search_for_name()" and guide me in the right direction.

Many thanks in advance
C

Code:

#include<stdio.h>
#include<conio.h>
#include<string.h>

/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
/*struct for a student */

typedef struct
{
	char name[20];
	int grade1;
	int grade2;
	int grade3;
	int grade4;
	int id;
}  names;

/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/

#define MAX 999

names names_database[20];
int index=0;
int id=100;
/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/

/* Functions used in this program */
void menu_controller(void);
void draw_menu(void);
int get_menu_option(void);
void process_menu_option(int option);
void add_new_name(void);
void search_for_name(void);
void search_for_id(void);

/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/

/*The main program*/

void main(void)
{
     menu_controller();
}

/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/

/* These are the specifications for the functions called*/

void menu_controller()
{
/*This function is the main controlling routine for our menu*/
int menu_choice=0;

/*The controlling loop for the whole programe*/
while(menu_choice !=9)
{
/*step 1 draw menu*/
draw_menu();

/*Step2 - Prompt for a user responce*/
menu_choice=get_menu_option();

/*Step3 - Action the users choice*/
process_menu_option(menu_choice);
}
}

/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/

void draw_menu(void)
{
/*This function simply draws the main menu - nothing else*/
clrscr();
/* Display the menu options*/
printf("\n\n\t\t      Student Search program\n\n");
printf("\t\t\t 1. Add new name and 4 exam percentages\n");
printf("\t\t\t 2. Search by name\n");
printf("\t\t\t 3. Search by ID number\n");
printf("\t\t\t 9. Quit\n");
}
/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/

int get_menu_option(void)
{
/*This function returns the menu option selected by the user*/
int option;

printf("\n\n\n\t\t    Please enter your option:  ");
scanf("%d", &option);
fflush(stdin);
return option;
}

/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/

void process_menu_option(int option)
{
/*An intiger to hold the value returned by getchar() */
int key;

/*This function eveluates each option and calls the appropriate function*/

switch(option)
{
	case 1 : add_new_name();
								break;

	case 2 : search_for_name();
								break;

	case 3 : search_for_id();
								break;

	case 9 : printf("\n\nThank you, the program will now exit....\n");
								break;

	default : printf("\n\nSorry that is not a valid option - press enter to continue");
							  key = getchar();
								break;
}    /* End switch*/
}    /* End process_menu_option() */

/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
/*These are the functions for our menu options, but they dont do much... */

void add_new_name(void)
{

clrscr();

/* Add the name and DOB to the database*/

printf("\n\n\t\t   Enter new name and Grades\n\n");
printf("Enter new name: ");
gets(names_database[index].name);
fflush(stdin);

printf("Please enter 4 grade marks in as a percentage value:\n\n");
scanf("%d%d%d%d",&names_database[index].grade1, &names_database[index].grade2,
&names_database[index].grade3,&names_database[index].grade4);
fflush(stdin);
names_database[index].id =id;
/* Increment the student array & id position*/
index++;
id++;
}

/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
void search_for_name(void)
{

int found = 0;
int result;
nt loop=0;
int key;
int average;
char name[20];
clrscr();

printf("Please enter the name to search for: ");
gets(name);
fflush(stdin);

while(found==0 && loop < MAX)
{
result = strcmp(names_database[loop].name,name);

if(result ==0)
{
average = (names_database[loop].grade1 + names_database[loop].grade2 +
names_database[loop].grade3 + names_database[loop].grade4) / 4 ;
printf("The average grade for %s is %d the ID number is %d\n",names_database[loop].name,average,names_database[loop].id);
found=1;
}
 loop++;

}
if(loop == MAX)
{
printf("NOT FOUND\n");
		 }

 key = getchar();



}
/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
void search_for_id(void)
{
int found = 0;
int loop=0;
int average;
int key;
int getid;
clrscr();

printf("Please enter the ID Number to search for between 100 & 999: ");
scanf("%d",&getid);
fflush(stdin);


if ( getid == names_database[loop].id)

				{
average = (names_database[loop].grade1 + names_database[loop].grade2 +names_database[loop].grade3 + names_database[loop].grade4) / 4 ;

printf("The average grade for %s is %d the ID number is %d\n",names_database[loop].name,average,names_database[loop].id);
found=1;

				}
if ( getid != names_database[loop].id)
{
	printf("NOT FOUND\n");

}
loop++;
key = getchar();
		
       



}

Thanks very much swoopy that seems to have done the trick

Welcome to the world of buffer overflow. Stop learning how to prevent it colinuk, it may hinder your ability to ever work at Microsoft.

About buffer overflows again, you need to be careful since sometimes they come up from simple mistakes such as typoes.

Example:

Code:

int array[200], i;

for(i = 0; i < 2000; i++) {
  array[i] = getchar();
}

In the above code, oops I typed 2000 instead of 200. This is another reason why I promote not using "magic numbers." Its harder to get away with simple typing erros when typing something like:

Example:

Code:

// assumes somewhere there is #define BUFFER_SIZE 200
int array[BUFFER_SIZE], i;

for(i = 0; i < BUFFER_SIZEE; i++) {
  array[i] = getchar();
}

Oops I typed an extra E on BUFFER_SIZE. Good thing this time is the compiler has no idea what I'm talking about and the crisis was averted.