what's wrong?

[belton180]

[CODE]../* Program function: Simulate the stack using a stack limit of 10. Display
a menu for the the following.
[C] Create a stack
[i] Insert an item in the stack
[P] Pop an item from the stack
[E] Peep/view the item at the top of the stack
[V] Current value of top
[W] View all items stored in the stack
[Q] Quit
*the stack accepts lowercase & uppercase characters only from A-Z
*any other symbol (e.g. punctuation marks, numbers, etc. should not be accepted by the program
*the stack should not accept DUPLICATE ENTRIES
Note:
*[C]create a stack
-deletes all items in the stack after a confirmation if
there are existing items stored in it.
*Display appropriate messages esp when
* trying to insert an item in a stack that is already full
* trying to pop items from the stack that is empty
* duplicate items in the stack ( note: lowercase and
uppercase letters are accepted as two different entries)
*insertion of invalid values
*/

#include<stdio.h>
#include<conio.h>
#include<ctype.h>
#include<string.h>
#define stacklimit 10
int top,i;
typedef enum boolean{FALSE, TRUE} boolean;

wrong(int error)
{
printf("\n");
switch(error)
{
case 0: printf("Incorrect input\n"); break;
case 1: printf("Please enter only Y or N\n"); break;
case 2: printf("Please enter a letter from A-Z\n"); break;
case 3: printf("Input is already in stack\n"); break;
}
}

createstack(char stack[])
{
for(i=0; i<stacklimit; i++)
stack[i]=NULL;
return stack[];
}
char initialize_stack(char stack[])
{
int error=0;
char choice= 'Y';
clrscr();
if(top!=-1)
{
do{
printf("Do you want to reintialize the stack? [Y/N]");
choice=toupper(getch());
if((choice!='Y')||(choice!='N'))
{ error=1;
wrong(error);
}
else;
}while(error!=0);
if(choice=='Y')
{ top=-1;
createstack(stack);
return stack[];
}
else;
}
else
{ top=-1;
createstack(stack);
return stack[];
}
}

int FULLSTACK()
{ int x;
if(top==stacklimit-1)
{ x=1;
return x;
}
else
{ x=0;
return x;
}
}

int checker(char input, char stack[])
{ int flag=0;
for(i=0;i<stacklimit;i++)
{ if(stack[i]==input)
flag=1;
}
return flag;
}

push(char input, char stack[])
{
char temp_stack[stacklimit];
int x=1;
top+=1;
for(i=0;i<stacklimit;i++)
temp_stack[i]=stack[i];
stack[0]=input;
for(i=0;i<stacklimit;i++)
{ stack[x]=temp_stack[i];
x++;
}
return stack[];
}

input_a(char stack[])
{
int error=0, full;
char input,check;
full=FULLSTACK();
if(full==1)
{ printf("Stack is already full");
return;
}
else
{
do{
printf("Please enter a letter from A-Z: ");
scanf("%c", &input);
check=toupper(input);
if(check!='A'||check!='B'||check!='C'||check!='D'| |
check!='E'||check!='F'||check!='G'||check!='H'||ch eck
!='I'||check!='J'||check!='K'||check!='L'||check!= 'M'
||check!='N'||check!='O'||check!='P'||check!='Q'||
check!='R'||check!='S'||check!='T'||check!='U'||ch eck
!='V'||check!='W'||check!='X'||check!='Y'||
check!='Z')
{ error=2;
wrong(error);
}
else if(checker(input, stack))
{
error=3;
wrong(error);
}
else;
}while(error!=0);
push(input, stack);
}
}

boolean EMPTYSTACK()
{
if(top==-1)
return TRUE;
else
return FALSE;
}

char pop(char stack[])
{
char x=0;
boolean empty;

empty=EMPTYSTACK();
if(empty==TRUE)
{
printf("Stack is empty");
getch();
return x;
}
else
{
x=stack[top];
top-=1;
return x;
}
}

view(char stack[])
{
for(i=0;i<stacklimit;i++)
printf("\n %d", stack[i]);
}
main()
{
int quit=0,error;
char choice , stack[stacklimit];
createstack(stack);
do{
clrscr();
printf("Main Menu");
printf("\n[C] Create a stack");
printf("\n[i] Insert an item in the stack");
printf("\n[P] Pop an item from the stack");
printf("\n[E] Peep/View the item at the top of the stack");
printf("\n[V] Current value of top");
printf("\n[W] View all items stored in the stack");
printf("\n[Q] Quit\n");
choice=toupper(getch());
switch(choice)
{
case 'C': initialize_stack(stack); break;
case 'I': input_a(stack); break;
case 'P': pop(stack); break;
case 'E': printf("\n%d", stack[0]); break;
case 'V': printf("\n%i", top); break;
case 'W': view(stack); break;
case 'Q': quit=1; break;
default: error=0; wrong(error); getch(); break;
}
}while(quit==0);
}..[\CODE]

[tyreld]

That is a good question. Does your code compile? If not what errors does it give you? If it does what kind of runtime problems do you have? This is information you should supply if you expect people to actually look at your code and help you fix it.

Just glancing at your code I can say this.

Several of your functions are missing return types. If you don't include a return type in the function signature the compiler will assume "int". On a poorly implemented compiler you might even get undefined behavior. To say the least it is poor style to not include a return type. If you are returning nothing then the return type should be "void".

if you aren't including a block of code in an "else" statement then you don't need it (ie "else;" is not necessary).

You can't return arrays in the manner you are trying to. Actually, you don't need to return the array. Unless you want to start dealing with pointers. Arrays in C are past by reference. So, any changes you make in your function effect the original array you passed into the function.

Finally, why not use "isalpha" which is defined in "ctype.h" for testing for a-zA-z instead of that ugly if condition you are using?

[belton180]

the problem is that it wont execute due to the ff. errors:

the return array thing

and something about the function prototypes of the boolean FULLSTACK and EMPTYSTACK not being defined in other functions

as for the isalpha, our teacher didn't discuss that at all...

[belton180]

never mind, figured it out by myself :), thanks for the tip about isalpha though, it really helped