fgets and scanf - couldn't diagnose new line bug.

hi,
the following code generates the newline bug. Please help.

Code:

---


#include <stdio.h>


int main (int argc, const char * argv[])
{
    /*Village Administration Database
    fields
    1. Name
    2. Age
    3. Sex
    */
    char name[1000][100];
    int age[1000];
    char sex;
    int gender;// boolean to verify gender
    int count = 0;
   
    // WELCOME
   
    fputs("WELCOME : Voters list Database\n",stdout);
    fputs("You can enter details of of 1000 voters(MAX)\n",stdout);
   
    for(;;)
    {
       
        printf("Please enter the details of Voter %d:",count+1);
    // NAME INPUT
   
    printf("Please enter the Name of the Voter :");
    fflush(stdin);
    fgets(name[count],100,stdin);
   
   
    // AGE INPUT
   
    fputs("Please enter the age of the Voter :", stdout);
    fflush(stdin);
    scanf(" %d",&age[count]);


    // SEX INPUT
    for(;;)
    {
        puts("Please enter Gender('M' for Male or 'F' for Female):");
        fflush(stdin);
        scanf(" %c",&sex);
        if(sex == 'm'|| sex=='f')
            break;
        {
            printf("ERROR!!!\nOnly 'M' or 'F' allowed\n ");
        }
    }
    gender = sex == 'm';
   
    //COUNT INCREMENT and CHECKING LIMIT
    count = count + 1;
    if(count == 999)
    {
        puts("YOU HAVE REACHED THE LIMIT OF ENTRIES");
        break;
    }
}
   
    // OUTPUT
   
    printf("NAME: %s",name[count]);
    printf("AGE: %d\n",age[count]);
    if(gender)
        printf("GENDER : MALE");
    else
        printf("GENDER : FEMALE");
   
    return 0;
}

---

BUG:

WELCOME : Voters list Database
You can enter details of of 1000 voters(MAX)
Please enter the details of Voter 1:Please enter the Name of the Voter :sandeep
Please enter the age of the Voter :29
Please enter Gender('M' for Male or 'F' for Female):
m
Please enter the details of Voter 2:Please enter the Name of the Voter :Please enter the age of the Voter :

---------------------------

On the second time around the loop, the program wouldn't stop for the name input.

please help... thanks in advance

fflush(stdin) is not good

The problem is that you're hitting the enter key after you enter the gender, so your program sees "m\n". That '\n' is not read by %c (it only sees the 'm'), so the '\n' is eaten by fgets(). There have probably been about a million threads on this topic, so you could search the forum. Basically, don't mix scanf() and fgets(), but if you have to, it's up to you to get rid of unwanted newline characters. fflush(stdin) is not the way to do this (although it might work on some weird platforms).

Stop using for loops with no loop control and putting a break inside. It's hard to read and error prone. Use a them the way they were intended:

Code:

---

#define MAX_ENTRIES 1000  // constants are way better than magic numbers
#define MAX_NAME  100
...
    char name[MAX_ENTRIES][MAX_NAME];
    int age[MAX_ENTRIES];

    for (count = 0; count < MAX_ENTRIES; count++) {
        ...
    }

---

You can't fflush(stdin), it results in undefined behavior. You can only flush output streams, but you don't need to do that in your program. Read this link for details. Read this link for other ways to clear the input buffer.

When reading the sex of the voter, use a do while loop. Do while loops are great for user input because they always run once, so you always ask the user for input once and read input once, and only repeat if they screw up:

Code:

---

do {
    print "enter gender"
    read sex
} while (tolower(sex) != 'm' && tolower(sex) != 'f');

---

Note that I used tolower to convert the input before checking. That way, if the user inputs an uppercase M or F (as your prompt suggests), your program will still work.

Lastly, the reason it doesn't ask for the name the second time around is because after they input the gender and press the enter key, there is a newline left in the input buffer. The second time through, fgets reads from the input buffer to the first new line, which is the first character, so it doesn't read a name. This demonstrates perfectly that your fflush(stdin) call doesn't work. You need to flush it in an appropriate manner.