Thread: Silly error

You are defining your addemail function inside of your main function. ISO C doesn't support nested function and your compiler should say that if you have all warnings turned on. You have to end your main function before defining your addemail function. Also, use int main() and return an exit status

Code:

#include <stdio.h>

void addemail();

int main()
{
    int choice;
    
    printf("Email whitelist");
    printf("(a) to add email, (c) to check email against list, (e) to exit.\n");
    printf("Choice: ");
    choice = -1;
    while (choice == -1)
    {
        choice=getchar();
    }
    switch (choice)
    {
        case 'a':
            addemail();
            break;
        case 'c':
           /* checkemail(); */
            break;
        case 'e':
            break;
        default:
            printf("Invalid Choice.");
            break;
    }
    return 0;
}
    
void addemail()
    {
        char buf[40];
        FILE *fp;
        
        printf("Enter email: ");
        fgets(buf, sizeof(buf), stdin);
        
        fp = fopen("emails","a+");
        fputs(buf,fp);
        fclose(fp);
        
        printf("\nEmail address %s added.",buf);
}

You can also check the return values of the functions you use, such as fopen, fgets, etc. We have a faq that might have some useful entries to you: http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

1. C does not support nested functions
2. You haven't written a function called addemail(), though you have managed to prototype it TWICE (check the semicolons)

Functions cannot be defined inside of other functions. Take your addemail function out of main and paste it after main (remembering to remove the semicolon).

Code:

#include <stdio.h>

void addemail(void);

int main(void)
{
    int choice;
    
    printf("Email whitelist");
    printf("(a) to add email, (c) to check email against list, (e) to exit.\n");
    printf("Choice: ");
    choice = -1;
    while (choice == -1)
    {
        choice=getchar();
    }
    switch (choice)
    {
        case 'a':
            addemail();
            break;
        case 'c':
           /* checkemail(); */
            break;
        case 'e':
            break;
        default:
            printf("Invalid Choice.");
            break;
    }

    return 0;
}  

void addemail(void)
{
    char buf[40];
    FILE *fp;
        
    printf("Enter email: ");
    fgets(buf, sizeof(buf), stdin);
        
    fp = fopen("emails","a+");
    fputs(buf,fp);
    fclose(fp);
        
    printf("\nEmail address %s added.",buf);
}

>while (choice == -1)
EOF isn't guaranteed to be -1, use the EOF macro instead.

> scanf("%c",&choice);
%c means char, and choice is an int

You're also using fgets elsewhere, so its going to mess up eventually. Just stick to fgets for everything

Code:

int main()  /* be specific about the return type */
{
    char choice[20];
    
    printf("Email whitelist");
    printf("(a) to add email, (c) to check email against list, (e) to exit.\n");
    printf("Choice: ");
    fgets( choice, sizeof choice, stdin );
    switch (choice[0])