Needs help on finding bug

[Atish Shrestha]

I am trying to build a menu based program. User gets to take records (min 5 & max 15) of students. after taking records, user gets to select 6 functionalities.
1. print records
2. Search by first name - prints record of the student with a given first name. If there are multiple students with the same first name, print records for all of them
3. Search by last name - prints record of the student with a given last name. If there are multiple students with the same lastname, print records for all of them
4. Sort by score - sort the records of studens according to their scores, and then print the sorted records
5. sort by last name
6. Exit the program

I was able to get my function 1 and 6 right. But for some reason, 2 to 5 functionalities dont work. Can somebody help me figure out what am i doing wrong?

here is the code

#define _CRT_SECURE_NO_WARNINGS#include <stdio.h>
#include<string.h>
#include<stdlib.h>


void menu();
void print_records(int size, char firstname[][20], char lastname[][20], float score[]);
void search_by_firstname(int size, char firstname[][20], char lastname[][20], float score[]);
void search_by_lastname(int size, char firstname[][20], char lastname[][20], float score[]);
void sort_by_score(int size, char firstname[][20], char lastname[][20], float score[]);
void sort_by_lastname(int size, char firstname[][20], char lastname[][20], float score[]);




int main(void)
{
	char fn[15][20]; // 15 rows 20 columns or 15 students 20 characters
	char ln[15][20]; // 15 rows 20 columns or 15 students 20 characters
	float sc[15]; // 15 scores max not all used
	int n = 0;
	int i = 0;
	int x = -1;
	char nametofind[20];


	printf("Please indicate the number of records you want to enter (min 5, max 15):\n");
	scanf("%d", &n);


	printf("Please input records of students (enter a new line after each record), with the following format \nfirst name last name score\n");
	for (i = 0; i<n; i++)
	{
		scanf("%s %s %f", &fn[i][0], &ln[i][0], &sc[i]);       //stores first name and last name characters in ith row starting at collumn 0
		// score is stored in sc array starting at index 0
	}
	do
	{
		printf("\n---you may access the records by---\n");
		printf("Print records (press 1)\n");
		printf("Search by first name (press 2)\n");
		printf("Search by last name (press 3)\n");
		printf("Sort by score (press 4)\n");
		printf("Sort by last name (press 5)\n");
		printf("Exit program (press 0)\n");
		printf("--------------------------\n\n");
		printf("Please a function by entering a value from 0 to 5.\n");
		scanf_s("%d", &x);


		printf("You have selected option: %d\n", x);
		switch (x)
		{
		case 1:
			print_records(n, fn, ln, sc);
			break;
		case 2:
			search_by_firstname(n, fn, ln, sc);
			break;
		case 3: search_by_lastname(n, fn, ln, sc);
			break;
		case 4: sort_by_score(n, fn, ln, sc);
			break;
		case 5: sort_by_lastname(n, fn, ln, sc);
			break;
		default: printf("Please only enter a number from 0 to 5\n");
		}
	} while (x != 0);
	return 0;
}
void print_records(int size, char firstname[][20], char lastname[][20], float score[])
{
	int i = 0;
	for (i = 0; i < size; i++)
	{
		printf("First Name: %s, Last Name: %s, Score: %.2f\n", firstname[i], lastname[i], score[i]);
	}


}
void search_by_firstname(int size, char firstname[][20], char lastname[][20], float score[])
{


	int i = 0;
	char nametofind[20];
	printf("Please enter the first name of student record you wish to print: ");
	/*fflush(stdin);*/
	gets(nametofind);
	for (i = 0; i<size; i++)
	{
		if (strcmp(nametofind, firstname[i]) == 0) // if nametofind is found in firstname array
		{
			printf("First Name: %s, Last Name: %s, Score: %.2f\n", firstname[i], lastname[i], score[i]);
		}
	}
}


void search_by_lastname(int size, char firstname[][20], char lastname[][20], float score[])
{
	int i = 0;
	char nametofind[20];
	printf("Please enter last name of student record you wish to print: ");
	/*fflush(stdin);*/
	gets(nametofind);
	for (i = 0; i<size; i++)
	{
		if (strcmp(nametofind, lastname[i]) == 0) // if nametofind is found in lastname array
		{
			printf("First Name: %s, Last Name: %s, Score: %.2f\n", firstname[i], lastname[i], score[i]);
		}
	}
}


void sort_by_score(int size, char firstname[][20], char lastname[][20], float score[])
{
	int i = 0;
	int j = 0;
	float tempscore;
	char tempfirstname[20];
	char templastname[20];


	// bubble sort
	for (i = 0; i<size - 1; i++)
	{
		for (j = 0; j<size - i - 1; j++)
		{
			if (score[j]>score[j + 1])
			{
				tempscore = score[j];
				score[j] = score[j + 1];
				score[j + 1] = tempscore;


				strcpy(tempfirstname, firstname[j]);
				strcpy(firstname[j], firstname[j + 1]);
				strcpy(firstname[j + 1], tempfirstname);


				strcpy(templastname, lastname[j]);
				strcpy(lastname[j], lastname[j + 1]);
				strcpy(lastname[j + 1], templastname);
			}
		}
	}
	print_records(size, firstname, lastname, score);
}


void sort_by_lastname(int size, char firstname[][20], char lastname[][20], float score[])
{
	int i = 0;
	int j = 0;
	float tempscore;
	char tempfirstname[20];
	char templastname[20];


	// bubble sort
	for (i = 0; i<size - 1; i++)
	{
		for (j = 0; j<size - i - 1; j++)
		{
			if (strcmp(lastname[j], lastname[j + 1])>0)
			{
				strcpy(tempfirstname, firstname[j]);
				strcpy(firstname[j], firstname[j + 1]);
				strcpy(firstname[j + 1], tempfirstname);


				strcpy(templastname, lastname[j]);
				strcpy(lastname[j], lastname[j + 1]);
				strcpy(lastname[j + 1], templastname);


				tempscore = score[j];
				score[j] = score[j + 1];
				score[j + 1] = tempscore;
			}
		}
	}
	print_records(size, firstname, lastname, score);
} 

[gemera]

        printf("Please a function by entering a value from 0 to 5.\n");
        scanf_s("%d", &x);

The buffer still contains the newline character..

Try placing this line of code after the 2 lines above to flush the buffer

while(getchar() != '\n');

btw gets() is now deprecated and fgets() should be used instead.

[Salem]

Also cross-posted here -> Cant get output right.

[Atish Shrestha]

Also cross-posted here -> Cant get output right.

Thank you very much. That worked. You are a life saver. thanx again

[Click_here]

I've changed a few things for you:

printf("Please enter the first name of student record you wish to print: ");
fflush(stdout);
fgets(nametofind, sizeof(nametofind), stdin);

The fflush(stdout) clears the output buffer (changed from stdin) - The C standard specifies that stdout does not have to flush (to the screen in your implementation) until it finds a new line. Although you probably will never see a system with that limitation, it is good practice to have that after a printf that does not end with a \n.

And the fgets instead of the gets is needed - It basically stops the user from breaking stuff. The syntax is very simple as well - array, size of array, stream.