/*
 * data.c
 * test opening and appending to
 * a file.
 */
 
#include <stdio.h>
 
int read_int(int *result);
char *read_string(char *string, int size);
 
int main(void)
{
    int n1, n2;
    char name[20];
    FILE *file_ptr;
 
     file_ptr = fopen("data.txt", "a");
    if(!file_ptr)
    {
        printf("Error opening file");
        return(1);
    }
    else
    {
        fprintf(file_ptr,"What's your name?: ");
        fprintf(stdout,"What's your name?: ");
        read_string(name, sizeof name / sizeof *name);
        fprintf(file_ptr,"%s\n", name);
    }
    printf("Enter value for first number: ");
    fflush(stdout);
    read_int(&n1);
    printf("Enter value for second number: ");
    fflush(stdout);
    read_int(&n2);
 
    fprintf(file_ptr,"n1 = %d\nn2 = %d\n", n1, n2);
    fclose(file_ptr);
 
    system("PAUSE");
 
    return(0);
}
 
int read_int(int *result)
{
        char ch, buffer[13];
        return fgets(buffer, sizeof buffer, stdin) && !isspace(*buffer) &&
        sscanf(buffer, "%d%c", result, &ch) == 2 && (ch == '\0' || ch == '\n');
}
 
char *read_string(char *string, int size)
{
    if(fgets(string, size, stdin) != NULL)
    {
        int len = strlen(string)-1;
        if(string[len] == '\n')
       {
           string[len] = '\0';
        }
        else 
        {
            int ch;
            do
            {
                ch = getchar();
            }
            while(ch != '\n' && ch != EOF);
        }
    }
    return string;
}