Thread: printing int in structure...weird

I have a block of code that takes input from stdin and stores it in a variable in a structure. then i go to print the contents of the structure but for some reason it keeps printing the last this entered from stdin.

after the user inputs their name and age, it goes back to the main menu where i choose to print names, option 3, which should print the name and age but it always prints 3 the last thing entered via stdin as opposed to the age previously entered

anyone know what the problem could be?

Thanks, ALain

ps. the program is nowhere neer complete for the task it needs to accomplish...ie. records placed in a sorted linked list..... so i appologize if bits and pieces confuse you the functions are not complete i just want to understand why i'm having this issue with stdin.

i'm compiling using gcc -ansi -Wall in a linux terminal.

Code:

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

#define MAX_LEN 250

struct node 
{
    char *name;
    int  age;
    struct node *nextName;
    struct node *nextAge;
};

typedef struct node NODE;

int drain_stdin()
{
    int c;

    while((c = getchar()) != '\n' && c != EOF );

    return c;
}
 
void addStruct(NODE *info)
{

    if (drain_stdin() != EOF )
    {
        printf("Enter name: ");
        fgets(info->name, MAX_LEN + 1, stdin);

        printf("Enter age: ");
        scanf("&#37;d", &info->age);
    }
    else
    {
        printf("An Error Has Occured\n");
    }

}

void removeStruct(NODE *info)
{

    if (drain_stdin() != EOF )
    {
        printf("Enter Name Of Desired Record To Be Removed");
        fgets(info->name, MAX_LEN + 1, stdin);
    }
    else
    {
        printf("An Error Has Occured\n");
    }
}

void printName(NODE *info)
{
    printf("%s %d\n", info->name, info->age);
}

void printAge(NODE *info)
{
    printf("%s %d\n", info->name, info->age);
}

/*
void exit(NODE *info)
{
    free(info->name)
    free(info);
}
*/

int main() 
{
    int choice;

    NODE *info;
    info = malloc(sizeof(NODE));
    info->name = malloc(sizeof(char)*MAX_LEN);

    do
    {
        printf("1. Add structure\n");
        printf("2. Remove structure\n");
        printf("3. Print names\n");    
        printf("4. Print ages\n");
        printf("5. Exit\n");
        scanf("%d", &choice);

        if(choice == 1)
        {
            addStruct(&info);
        }
        else if(choice == 2)
        {
            removeStruct(&info);
        }

        else if(choice == 3)
        {
            printName(&info);
        }
        else if(choice == 4)
        {
            printAge(&info);
        }/*
        else if(choice == 5)
        {
            exit(&info);
        }*/      
        else
        {
            return 0;
        }
        
    }while(choice != 5);    

    return 0;
}

I don't see why that should be.

Can you print "info->age" just after you read it in? Not that there is a reason why it should change, of course.

--
Mats

How about posting what it was, just to satisfy our curiosity? And you never know, it may help someone else too...

--
Mats

Code:

#include <strings.h>

What's that? Seriously, that's a non-standard header file, and since you don't seem to be using anything from it, you probably shouldn't include it.

sizeof(char) is always 1.

Code:

    info->name = malloc(sizeof(char)*MAX_LEN);
/* ... */
        fgets(info->name, MAX_LEN + 1, stdin);

Looks like you might be going one too far there. Don't add 1 to the fgets() size.

Code:

    NODE *info;
/* ... */
            addStruct(&info);
/* ... */
void addStruct(NODE *info)
{

I think you have one too many levels of indirection there. Passing just "info" is more likely to be what you want. This applies to the other functions as well.

Nice drain_stdin() function, BTW.