invalid conversion from `char*' to `char'

[Ron]

This is a snippet of code

FROM THE MAIN FUNCTION:

Push(s1,check,line); /*s1 is a structure with elements 	Element *contents;
                                                        int top;
	                                                int lineST;
                      check is a string array
                      line is an integer */

PUSH FUNCTION ACCESSED FROM ANOTHER C FILE:

void Push(stackST *stackP, char* element, int line)
{

  /* Put information in array; update top. */
  char newelement[20];
  int i=0;
  int length = strlen(element);
  for (i=0;i<=length;i++)
	newelement[i++]=putchar(*element++);
  newelement[i] = '/0';
 stackP->contents[++stackP->top] = newelement;
  stackP->lineST=line;
}

I get the following warning and error for the line marked in bold
warning: multi-character character constant
error:invalid conversion from `char*' to `char'

I have twisted the code a lot. But cant figure the solution to this problem.

[King Mir]

Apparently Element::contents is a char pointer or char array, and when indexing that, you get a char. Newelement is a char array.

[Ron]

yes you are right, contents is a pointer.
hmmm....
so what would the syntax be if i were to point it to newelement?

[tabstop]

(1) The null character is \0, not /0.
(2) If you want to change the pointer, just use the pointer. I have no idea what pointer you're trying to change -- stackP[top].contents, perhaps?

[Salem]

> for (i=0;i<=length;i++)
> newelement[i++]=putchar(*element++);
Why does this increment i twice each time?

> stackP->contents[++stackP->top] = newelement;
Assuming you fix the left to be a char*, you're still pointing at a local variable - this is a big no-no

You need to use malloc to allocate newelement if you want it to persist longer than the life of this function.

[Ron]

I have already done so when initializing the stack

void StackInit(stackST *stackP)
{
  stackElement *newContents;

  /* Allocate a new array to hold the contents. */

  newContents = (stackElement *)malloc(sizeof(stackElement) * 10);

  stackP->contents = newContents;
  stackP->lineST = 0;
  stackP->top = -1;  /* I.e., empty */
}

Thanks for pointing out about the increment.

[Salem]

What's a stackElement
Perhaps you're meant to strcpy it?

[Ron]

stackelement is a type-defined character defined.

Also, for some reason the error now doesnt show up anymore in the push function.
But the error comes up in the line of code that calls the push function.

Push(s1,check,line); /*s1 is a structure with elements 	Element *contents;
                                                        int top;
	                                                int lineST;
                      check is a string array
                      line is an integer */

error: invalid conversion from `char*' to `stackElement'
error: initializing argument 2 of `void Push(stackST*, stackElement, int)'

[tabstop]

Apparently stackElement is not a char *. So again: what is it?

[Ron]

I get so impatient with UNIX.......

I dont know what the 2nd argument is supposed to be a string.
I dont know why it refers to stackelement

[tabstop]

This has nothing to do with UNIX and everything to do with your program. Look at your function: void Push(stackST*, stackElement, int). That second argument says stackElement. How did you define stackElement, and what do you want it to be?

[Ron]

I figured what went wrong. I gave the wrong parameter in the explicit function call in the header file. Thanks for your help.