Thread: validating with a char.

im having problems with strings or char's in c.

Code:

#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <stdlib.h>

void main (void)
{
	int mark = 0;
	char grade;
do
	{
printf("what was your exam mark: ");
scanf("%d",&mark);
	}
while( (mark < 0 ) || (mark >100));

do
	{
	printf("what was your grade : ");
	scanf("%c",&grade);
	}
	while((grade !='a' )||(grade !='b')||(grade !='c'));
	clrscr(); 
	gotoxy(14,14);
	printf("your mark was %d and your grade was %c",mark , grade);
	fflush(stdin);
	getchar();
}

What i am wondering is am i declaring the char right to be able to test it. Im really looking to Validate the input so people can only enter a,b or c.
does anyone have a better way?
im pretty new to this and have read the faq and could not find anything there to help.

any help would be greatly appreciated.

Try this out:

Code:

#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>          //you need this for the tolower function

int main () //start with int main NOT void main 
            //(don't really know why, just ask the experts here!)
{
	int mark = 0;
	char grade;
do
	{
printf("what was your exam mark: ");
scanf("%d",&mark);
	}
while( (mark < 0 ) || (mark >100));   //this is OK, don't know y FCF  said otherwise

while(1)                //infinite loop
	{
	printf("what was your grade : ");
	grade=getchar();
	
                if(tolower(c)=='a' )||(tolower(c)=='b')||(tolower(c)=='c'))
                {
                 break;
                }
         }
	clrscr(); 
	gotoxy(14,14);
	printf("your mark was %d and your grade was %c",mark , grade);
	fflush(stdin);
	getchar();
}

@ James00 you are a star mate. i was not expecting somone to take the time out to actually write the changes for me but you did.

Big thanks to everyone that helped. this forum seems a excellent place to learn i think im gonna stick around.

Originally posted by FCF


Sorry for the mistake..

Pls examine this:
while( (mark < 0 ) || (mark >100));
How abt if the user enter 25? Pls think.


I feel sleepy...

lol same here is is 3:30 in the morning and im all out of coke.

Glad that I could help you out 4play!!! Anyway, I really recommend that you visit here often, and ask for help here when needed, it really is a great forum with lots of guys with a lot of experience. I have also started programming C a couple of months ago, and I have found answers to all my questions here. Hope that you do come here often!