linked student list need help

[tmitch]

I have a problem that I need some help with. I am trying to create a program that will create an intial list of students and grades, and that will allow me to modifyu,delete, and display the linked list. I have created the following code, which ruins with no errors, but it does not give me the intial list of students. any advice???

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

struct studentInfo {
	char name[32];
	int grade;
	studentInfo * next;
};


studentInfo * student_list;


void printStudent(studentInfo * stud)
{
	printf("Student: %s\n", stud->name);
	printf("\tgrade: %d\n", stud->grade);
}

void printAllStudents(void)
{
	struct studentInfo * current = student_list;
	if (current != 0) {
		while (current != 0) {
			printStudent(current);
			current = current->next;
		}
	} else {
		printf("Error: No students have been entered yet!\n");
	}
}

void addStudent(void)
{
	printf("Creating a new student...\n");
	studentInfo * temp = (struct studentInfo*) malloc(sizeof(struct studentInfo));
	printf("Enter student name:");
	gets(temp->name);
	printf("Enter the student's grade:");
	char buffer[8];
	gets(buffer);
	printf("Adding student %s to the list...", temp->name);
	temp->next = student_list;
	student_list = temp;
	printf("Done!\n");
}

void getStudentInfo(void)
{
	printf("Enter the name of a student:");
	char search[32];
	int found = 0;
	gets(search);
	printf("Searching the list...");
	struct studentInfo * current = student_list;
	while ((current != 0) && !found) {
		if (!strcmp(current->name, search)) {
			found = 1;
		} else {
			current = current->next;
		}

	}
	printf("Done!\n");
	if (current != 0) {
		printStudent(current);
	} else {
		printf("No student by that name exists in the database\n");
	}
}



void main(void) {
	char current = 0;
	student_list = 0;
	printf("Welcome to Theresa's student manager.\n");
	while (current != 'Q') {
		printf("Enter a choice:\n");
		printf("[V]iew all students\n");
		printf("[A]dd a student\n");
		printf("[G]et info on a student.\n");
		printf("[Q]uit.\n");
		current = getc(stdin);
		/* Need this to pull off the return */
		getc(stdin);

		switch (current) {
		case 'V':
		       printAllStudents();
		       break;
		case 'A':
		       addStudent();
		       break;
		case 'G':
			getStudentInfo();
			break;
		case 'Q':
			printf("See ya later...\n");
			getc(stdin);
			break;
		default:
			printf("Error: Unkown command!\n");
		}
	}
	/* Free up all memory we've used */

	struct studentInfo * temp = student_list->next;
	while (student_list != 0) {
		free(student_list);
		student_list = temp;
		temp = temp->next;
	}
}

[BobS0327]

Well, unfortunately, your addStudent function just isn't adding students.

Also, use the first struct pointer to cycle thru your list.

Good luck
Bob

struct studentInfo {
    char name[32];
    int grade;
    studentInfo * next;
}*first;

void addStudent(void)
{
    char buffer[8] = {0};
    struct studentInfo  *temp = NULL;
    struct studentInfo *current;
    printf("Creating a new student...\n");
    /* Allocate memory for the new structure that first->next will
       point too. Then clear it with memset to be certain we're NOT
       pointing to incorrect address.  It's better to be safe than sorry... 
     */
    temp= (struct studentInfo *)malloc(sizeof(struct studentInfo));
    memset(temp, 0, sizeof(struct studentInfo));
    /* We must allocate memory for first entry. */
    if(first == NULL) {
        first = (struct studentInfo *)malloc(sizeof(struct studentInfo));
        memset(first, 0, sizeof(struct studentInfo));
        current = first;
    } 
    else {
        current = first;
        /* Follow the links through the list until we hit the end */
        while(current->next != NULL)
            current = current->next;
    }
    current->next = temp;
    printf("Enter student name:");
    gets(current->name);
    printf("Enter the student's grade:");
    gets(buffer);
    current->grade = atoi(buffer);
}

[dude543]

Are u compiling it as c++ code ?

In ansi c :
A. declaring arguments should be done before anything else.
B global varibales static or external are guraranteed to be initalized to zero;

[quzah]

In C99:

A. declaring arguments should be done before anything else, because it looks like crap otherwise, and makes for ugly code, but it's not required.

B. B is for Beer, it's good enough for me.

C. Cookie, cookie, cookie starts with C!

Quzah.

[Harbinger]

void main
gets(buffer)
casting malloc....

I'm gonna puke!!!!