Thread: Loopy Problem!!!

I'm doing a program for school and this piece of code won't work...

// This function gets the user to input the percent grade and returns the
// rounded version of that value.
int input_grade (void)
{

// This variable is the percent grade and is input by the user. It is set to 150
// so the 'while' loop will function correctly.
float per_grd=150;

// This variable hold the value of the rounded percent grade.
int round_grd;


// This loop lets the user re-enter the percentage grade if it is invalid.
while (per_grd>100 || per_grd <0)
{

// Gets the user to input the percentage grade.
printf ("Enter percentage grade: ");
cin >> per_grd;

// The following checks it make sure the input is valid and if it is not, it
// displays an error message.
if (per_grd>100 || per_grd <0)
{

// Prints an error message to the screen, gets the user to press
// any key to continue then clears the screen. The loop then restarts.
printf ("\nTHAT IS AND INVALID ENTRY...PLEASE RE-ENTER!\n\n");
system ("PAUSE");
system ("CLS");


}

else
{

// Calls the round function then assigns the value to the 'round_grd'
// function.
round_grd=per_grd_round(per_grd);

}

}

// Returns the value of the rounded grade.
return round_grd;
}

... When you enter a letter the loop works, but it won't let you re-enter the value and just loops continuously.

Thanx, Ian

PS. I have attached the full code... please take a look and reply...

I'm not too sure of the problem...

Maybe you could state your while loop as while(1) and then use a break statement in your if statement to exit the loop.

Here is an easier way to round a number I think just FYI (you'll have to include math.c)

int round(double x)
{
if (ceil(x)-x <= x-floor(x))
{
return (int)ceil(x);
}
else
{
return (int)floor(x);
}
}

Try this:

// This loop lets the user re-enter the percentage grade if it is invalid.
while (per_grd>100 || per_grd <0)
{

// Gets the user to input the percentage grade.
printf ("Enter percentage grade: ");
cin >> per_grd;

if (cin.fail())
{
cin.clear();
cin.seekg(0);
per_grd = 150;
}

// The following checks it make sure the input is valid and if it is not, it
// displays an error message.
if (per_grd>100 || per_grd <0)
{

// Prints an error message to the screen, gets the user to press
// any key to continue then clears the screen. The loop then restarts.
printf ("\nTHAT IS AND INVALID ENTRY...PLEASE RE-ENTER!\n\n");
system ("PAUSE");
system ("CLS");


}

else
{

// Calls the round function then assigns the value to the 'round_grd'
// function.
round_grd=per_grd_round(per_grd);

}

}

Originally posted by JasonLikesJava

Maybe you could state your while loop as while(1) and then use a break statement in your if statement to exit the loop.

That's called bad programming...It's hard to look through code with gotos and breaks.

What???? I've never heard that a break is a bad programming technique.

Anyways, in the code it just seemed strange that the while and if say the same thing so it seemed clearer to me to use break.

I agree with that gotos are bad and have never used them since I left programming on my TI-83 during Algebra I (never really learned to use them since they aren't needed).

Right, in the second case it is shorter... in this case, but I don't think that is the case in the originally posted program.

Strike that.... FIRST case is shorter... but you know what I mean.