Switch/Case Fallthrough BUG

[DaemonCoder]

I have a switch/case statement using numerics for a menu, but when i enter an alphanumeric statment it goes into a loop printing my menu and the default statement from switch/case the default statement. The only way to end it is ctrl-c. the code is below. Can someone please explain this quirk to me?

#include<stdio.h>
#include<stdlib.h>
int CHOICE;
int LTENC[11];
 
//SNIPPED - cArrayModify(); / pLastTen();
 
void doNothing()
{     
    printf("\n");
    cArrayModify();    
}
 
void invalidChoice()
{
    printf(" Invalid Choice!! \n");    
    cArrayModify();
}
 
void menu()
{
    cArrayModify();
    printf(" \n \n"); 
    printf(" Menu: \n");     
    printf(" 1 - Print Menu \n");
    printf(" 2 - Do nothing \n");    
    printf(" 3 - Exit \n \n"); 
    pLastTen();
 
}
 
int programexit()
{
    printf("\n Exit Conditions met, program will now exit!\n");
    return 0;
}
 
void commandlp()
{
    while(1)
    {
        printf("-> ");
        scanf("%d",&CHOICE);
        switch(CHOICE)
        {
            case 1 :  menu(); 
            break;
 
            case 2 : doNothing();
            break;
 
            case 3 : programexit();
            exit(0);
 
            default: invalidChoice();
            break;
 
        }
    }
 
}
 
 
int main()
{
 
    menu();
    commandlp();
 
}

[oler1s]

Please give an example. Show the program input you used, a bit of sample output, etc.

[gpraghuram]

You are only coming out of switch statement and not the while loop.
The break u have given is only for switch statement.
So you should also exit from while loop or change while to if

Raghuram

[DaemonCoder]

 Menu:
 1 - Print Menu
 2 - Do nothing
 3 - Exit
 
 
 Last ten commands: 0, 0, 0, 0, 1, 1, 1, 1, 5,-> s
 
->  Invalid Choice!!
->  Invalid Choice!!
->  Invalid Choice!!
->  Invalid Choice!!
->  Invalid Choice!!   //  this loops to this with no further user input...
 
-> ^C

The reason i didnt break oout of the while loop is because this is a menu with an exit function. I dont want it to exit unless the user says to exit.

[oler1s]

Yeah, there's a bug in your code. And it's not the switch statement. I was going to type up a large post, but I realized that an article on scanf explains the issue.

[DaemonCoder]

So using scanf() is my problem... So now i have another issue...

 
<SNIPPED>
while(1)
    {
        printf("-> ");
        sscanf("%*s",CHOICE_STRING);
 
        CHOICE = strcmp (CHOICE_STRING, commandListVariable);
// if  commandListVariable == "exit" and CHOICE_STRING == "exit"
// what does this return...???
 
 switch(CHOICE)
        {
 
<snipped>
 
 

Do i have to create a seperate variable for each command or is there a way to use strcmp for a direct comparison to a literal so that i get the correct command executed in the switch statement??

The information that i found says "Returns an integral value indicating the relationship between the strings". How do i 'predict' what the valuse of the comparison will be?