Thread: Char arrays, pointers and if statements

Hello

I have a program that is working how I want it, but I am distressed by a compiler warning. I therefore assume I have poor code and would like to know if this is the case.

Basically what I have is the following:
- A linked list containing these nodes

Code:

struct node{
	int number;
	char *ID;
	struct node *next;
};

- I then have a function which takes an ID and tries to find if the ID is currently present in the list. If it is, then return the number associated with the ID. Else I need to display the name of the ID that isn't in the list

Code:

int Getnumber(char *name[]){
	search = head;              //set searchptr to head of the list
	while (search->next != NULL){
		if (search->ID == *name){
			return search->number;
		}
		search= search->next;
	}
	if (search->ID == *name){
			return search->number;
	}	
	else{
	printf("ID %s is not in the list\n",name);
	exit(1);
	}
}

Given that I call the function like so : Getnumber(ID); where ID is defined as char *string;

any idea why I get this warning message?

Code:

warning: format ‘%s’ expects type ‘char *’, but argument 2 has type ‘char **’

Regards,
James

name, as you have it declared, is an array of strings. If you just wanted name to be a single string, then that's just char *name. (You would then not use *name in all your comparisons.)

I do in fact want just a single string, thanks.

The code now looks like this:

Code:

int Getnumber(char *name){
	search = head;              //set searchptr to head of the list
	while (search->next != NULL){
		if (search->ID == name){
			return search->number;
		}
		search= search->next;
	}
	if (search->ID == name){
			return search->number;
	}	
	else{
	printf("ID %s is not in the list\n",name);
	exit(1);
	}
}

I get no compiler warning, but the code no longer functions correctly. It says it cant find an ID that I know for sure is in the list.

Remember that == compares values, and the value of name is a pointer. If you want to compare the content being pointed to, you want to use strcmp.

Ah thanks, I never heard of strcmp() before. Usually just deal with numbers!

code is now working fine, thanks for the fast help!