Thread: Having troubles compiling

Next time, please copy-paste the error message from your compiler. It helps us immensely.

The reason the compiler stops is because you use getNumber. getNumber() with parentheses calls the function. getNumber without parentheses is a pointer to said function. You can't go assigning a pointer (getNumber) to an int (aNumber). Also, a single = is for assignment. A double == is for comparison. You probably want the latter, and you probably don't want to call getNumber() twice in that case statement.

Your getNumber function looks horribly broken. You're while loop is infinite and will only print "Enter a number...". Your if statement is missing a closing curly bracket }. I would use a do while loop, and I would probably recommend you use curly brackets for every if, while, for and do-while loop, even if you don't need them.

And fix your indenting (look into the auto-indent feature of your editor/IDE), it will make several of these errors more obvious.

There's quite a bit more work to do, but that should keep you busy for a while.

Ok, now I made to here. The compiler started going, then stopped on 'Link Errors'. My professor didnt even tell us about these...

here are the messages:

[Linker error] undefined reference to `prinf'
[Linker error] undefined reference to `prinf'
ld returned 1 exit status

Code:

#include <ctype.h> // to use the upper function
#include <stdio.h>
#include <stdlib.h>

char getMenuChoice();
int getNumber();


int main() {
//Declare variables here
     int aNumber = 0;
     float average = 0.0;
     int high = -1;
     int low = 1001;
     int total = 0;
     int count = 0;
     char getChoice = ' ';
     
     
     do{
        getChoice = getMenuChoice();
        switch (getChoice) {
               
               case 'A': 
                    aNumber == getNumber();
                    total += aNumber;
                    count++;
                    
                    if (aNumber = getNumber())
                       high = aNumber;
                    if (aNumber < low)
                       low = aNumber;
                    
                    printf("Inside of A\n");
                    break;
                    
               case 'B':
                    
                    average = (double)total / count;
                    printf("The avg is %.2f\n");
                    system("pause");
                   break;
               case 'C':
                    
                    printf("The Highest Value WAS %i\n", high);
                    system("pause");
                     
                    break;
               case 'D':
                    prinf("The Lowest Number is %i\n", low);
                    system("pause");
                    break;
               case 'E':
                    printf("Inside of E\n");
                    break;
               case 'F':
                    prinf("Inside of F\n");
                    break;
               case 'G':
                    printf("Inside of G\n");
                    break;
                    }//End switch
                    
        } while (getChoice != 'G');
     
   system("pause");
   return 0;
}      // end of Main


char getMenuChoice() {
     char result, choice = ' ';
     
     
       while (result != 'A' && result != 'B' && result != 'C' && result != 'D' && result != 'E' && result != 'D' && result != 'E'
     && result != 'F' && result != 'G') {
     
     system("cls"); //clear the screen
     
     printf("*********************************\n");
     printf("A) Enter a number between 0 and 1000\n");
     printf("B) Display the average\n");
     printf("C) Display the Highest Number\n");
     printf("D) Display the Lowest Number\n");
     printf("E) Display the total of all numbers entered so far\n");
     printf("F) Display how many numbers were entered during the session\n");
     printf("G) Quit the program\n");
     scanf("%c",&result);
     result = toupper(result);
     
     choice = getchar();
     fflush(stdin);
     choice = toupper(choice);  //BUILT IN FUNCTION; caps//lower recognized
     
     if (result != 'A' && result != 'B' && result != 'C' && result != 'D' && result != 'E' && result != 'D' && result != 'E'
     && result != 'F' && result != 'G') {
               
               printf("You must enter A - G only \n");
               system("pause");
               
               }//End IF
               }
     
     
     
    
     return result;
}//End of getMenuChoice


int getNumber () {
    int result = -1;
    
    while (result < 0 || result > 1000)
    
    
    printf("Enter a number between 0 and 1000: ");
    scanf("%i", &result);
    
    if (result < 0 || result > 1000) {
    printf("You must enter a number between 0 and 1000\n");
    system("pause");
    
    return result;
    
}// End IF
}//end of getNumber function

For starts... your getMenuChoice function is not really a good plan... the menu and the command switch are so closely linked that you had to go into wild contrivancy to separate them... moreover it's only used in one place in the code. Move it back into the main() function and integrate it into your do-while() loop.

In get number you are using system(pause) ... don't do that. Simply print the error message and let the function cycle back up to asking for information. The extra keystrokes will annoy the heck out of your operators...

In fact don't use system() calls at all, if you can get out of it.

For your loop running wild... it's very likely the user (you) is entering lower case characters which your convoluted menu system can't deal with.

Originally Posted by Wolf776

My professor is trying to get us to use functions. So we are made to do it that way.

Then he is teaching bad programming practice...

A properly written function does one thing... parameters go in the top, answers come out the bottom.
Splitting up tightly coupled code most often does nothing but cause problems... as you've discovered.

Well either, ie: A or a, it still comes out the same

EXACTLY what is it doing... It goes into the menu display and never comes back?

I found the issue, I didn't put the brackets after the fflush; to stop the while. I think he was trying to show, that you can easily put stuff into functions

Originally Posted by Wolf776

I found the issue, I didn't put the brackets after the fflush; to stop the while. I think he was trying to show, that you can easily put stuff into functions

You may want to take a closer look at that setup... you are asking for input TWICE in that function (lines 88 and 91) and assigning them to two different variables...

Moreover; fflush(stdin) is depricated (meaning you shouldn't use it in new code) because flushing input queues is highly unreliable and compiler dependent. Flushing is for output functions to ensure data is written, not input...

Which do you flush at home... your taps or your toilet?

fflush(stdin) results in undefined behavior, don't use it. Read Cprogramming.com FAQ > Why fflush(stdin) is wrong and Cprogramming.com FAQ > Flush the input buffer.

As for the need for functions, don't put menu choice error checking in the menu function. Try something like:

Code:

char getMenuChoice(void) {
    char choice;

    system("cls"); //clear the screen

    printf("*********************************\n");
    printf("A) Enter a number between 0 and 1000\n");
    printf("B) Display the average\n");
    printf("C) Display the Highest Number\n");
    printf("D) Display the Lowest Number\n");
    printf("E) Display the total of all numbers entered so far\n");
    printf("F) Display how many numbers were entered during the session\n");
    printf("G) Quit the program\n");
    scanf("%c", &choice);

    // code to flush the input buffer you learned from the second link above

    return toupper(choice);
}//End of getMenuChoice

That uses a function, and does one thing and does it well. Now, the checking can be done in main. You can take advantage of the "default" case label for error checking:

Code:

    char choice;

    do{
        choice = getMenuChoice();
        switch (choice) {
            case 'A':
                 // do A stuff
                break;
            case 'B':
                // do B stuff
                break;
...
            case 'F':
                // do F stuff
                break;
            case 'G':
                // do nothing, we're just going to quit
                break;

            // this is a "catch-all" that will cover any invalid menu choice
            default:
                printf("You must enter A - G only \n");
                system("pause");
                break;
        }//End switch
     } while (choice != 'G');