c - swap function for singly linked list of strings

Question

I am trying to implement a swap function for my linked list.

The initialization is as follows

typedef struct node
{
    char data[50]; // data
    struct node *next; // a pointer to next node
} Node;

typedef Node* NodePtr;

In one of my functions I try to swap two functions by using

swap(&(p->data), &(q->data));

where p and q are NodePtr 's.

My swap function is as follows:

void swap(char *a, char *b)
{
   char *t; // temporary

   t = *a;
   *a = *b;
   *b = t;
} // end swap()

I keep getting the following error : [Error] cannot convert 'char (*)[50]' to 'char*' for argument '1' to 'void swap(char*, char*)'

I know this means that I need to change how I declare my functions but I am just not sure how to change them to correctly do what I want.

Answer 1

Check the below code on how to swap two strings in a structure.

#include <stdio.h>

struct a
{
    char c[50];
};

void swap(char *p,char *q)
{
    char t[50] = "";
    strcpy(t,p);
    strcpy(p,q);
    strcpy(q,t);
}
int main(void) {
    struct a *A = malloc(sizeof(struct a));
    struct a *B = malloc(sizeof(struct a));
    strcpy(A->c,"some");
    strcpy(B->c,"string");
    printf("%s %s\n",A->c,B->c);
    swap(A->c,B->c);
    printf("%s %s\n",A->c,B->c);
    free(A);
    free(B);
    return 0;
}