Thread: Program thrown into loop when character entered instead of flaot

Thanks,

When I woke up this morning, thats what I was thinking (isdigit). Then I logged on here and saw your comment, I entered it and it works well. Thanks.

Can you impose a time limit on a command like getchar() ???

I got the program to stop and not loop if the user enters a character rather than a number, but now the program stops and waits for the user to hit a key when they enter a number.

Code:

//   Enter purchase amount and verify purchase amount
	do { // do-while loop start
		printf("\n\nEnter the total purchase amount: $");
		scanf("%f", &fPurchase_Amount);
	if (fPurchase_Amount <= 0.0)
		printf("\nYou did not enter a valid number, please try again");
	if (isdigit(fPurchase_Amount));
	else
		getchar();
	} //end do-while loop	
	while (fPurchase_Amount <= 0.0);

Originally Posted by alekbabich

Can you impose a time limit on a command like getchar() ???

I got the program to stop and not loop if the user enters a character rather than a number, but now the program stops and waits for the user to hit a key when they enter a number.
...

One way is to schedule an alarm signal (SIGALRM) to be sent to the process after a number of seconds have elapsed, given as an argument to alarm().
Write a signal handler that sets a flag upon receipt of SIGALRM; check the value of flag in the caller to decide whether to continue or exit the program.