Help with a very simple C program....Already written, not working right!

Hey,

I have to write a program for class that takes in a last name, first name, and exam score and stores them into seperate arrays. No structs in this however. Then I have to print the high score, low score, and avg score. Thats it. I thought that I had it right but it doesnt work correctly when I run it, even though it compiles fine.

Heres my program...

Code:

#include <stdio.h>

#define CLASS_SIZE 10
#define NAME_SIZE 20

int getInfo(char[][20], double[], char[][20], int);
void printResults(char[][20], double[], char[][20], int);
void doCalcs(double[], int);

int main()
{
        int count = 0;
        char first[10][20];
        char last[10][20];
        double score[10];

        count = getInfo(first, score, last, count);
        doCalcs(score, count);
        printResults(first, score, last, count);

        return 0;
}


int getInfo(char first[][20], double score[], char last[][20], int count)
{
        char again='y';

        while(again=='y')
{
        printf("Please enter the student's first name -- ");
        scanf("%s", first[count]);
        printf("Please enter the student's last name -- ");
        scanf("%s", last[count]);
        printf("Please enter the exam score --  ");
        scanf("%lf", &score[count]);

        count++;

        printf("Would you like to enter another record? (y/n)");
        //scanf("%c", &again);
        scanf("%s", &again);
}
        return count;
}

void doCalcs(double score[], int count)
{
        int i;
        double high;
        double low = 105;
        double avg;
        double total;

        for(i=0; i<count; i++)
        {
        if(score[i] > high)
                {
                high = score[i];
 		}
        if(score[i] < low)
                {
                low = score[i];
                }
        }

        for(i=0; i<count; i++)
        {
        total = total + score[i];
        }

        avg = total/count;

        printf("Total number of students = %d\n", count);
        printf("Highest score = %lf\n", high);
        printf("Lowest score = %lf\n", low);
        printf("Average score = %lf\n", avg);
}

void printResults(char first[][20], double score[], char last[][20], int count)
{
        int i;
        for(i=0; i<count; i++)
        {
        printf("%s, %s %4.2lf\n", last[i], first[i], score[i]);
        }
}

This is what Im getting when I enter some information...

Please enter the student's first name -- Joe
Please enter the student's last name -- Smith
Please enter the exam score -- 30
Would you like to enter another record? (y/n)y
Please enter the student's first name -- Bob
Please enter the student's last name -- White
Please enter the exam score -- 80
Would you like to enter another record? (y/n)n
Total number of students = 2
Highest score = 0.000000
Lowest score = 0.000000
Average score = 37270968922511555218815399770931566435968430750338 28121034433494206368125488490594734490445484833985 42932704708245693379119842581045603106586418751351 90047137854599889866604204928347406994246874588887 4194112758707602325504.000000
7N, 0.00
, 0.00
Segmentation fault


Any help would be greatly appreciated!!!! Thank you!

Initialize all the variables involved in your calculations, for example

double high = -105.0;
double low = 105.0;
double total = 0.0;
double avg = 0.0;

Utherwise you will have an undetermined initial value for these very important numbers.

scanf("%s", &again);
you cannot do this

even if the user pressed only 1 char and enter
scanf will store 2 chars in the pointer provided - the char pressed and nul-char

if user enters something longer - even more characters will be stored, while you have only place for 1 char

Thank you so much! It works! I had no idea!

For some reason when I put %c in there instead, it wont let me enter a character! Its just like the statement is not even there!

I have no idea why my program just worked once when I changed the initializations, and now its not working again after no other changes...weird

Am i allowed to say scanf("%c", &again) in that spot? Because like I have it commented out, if I have it just like that, the program does not pause to allow me to enter a char and just keeps running outside the loop and finishes...

ya u can use scanf("%c", &again).. but before that u should clear the buffer.. for that u can just type getchar();

That works! Thats crazy, why do you have to clear the buffer, and why does getchar() do it for you! Ha off to google....

thats because in ur program, inside while loop ur adding a value to the charecter variable. as again is a charecter variable only a charecter gets in to it. but as you press enter after entering a charecter variable even the \n value also will be in the buffer of stdin. so by using getchar() function we are just emptying the buffer.

Awesome i got ya! Thank you so much!