redefinition; different basic types 오류

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <string.h>

#define CAPACITY 100
#define BUFFER_SIZE 20 

char* names[CAPACITY];			/*names*/
char* numbers[CAPACITY];		/*phone numbers*/
int n = 0;						/*number of people in phone directory*/

void add();
void find();
void status();
void remove();

int main(void) {
	char command[BUFFER_SIZE];
	while (1) {
		printf("$ ");
		scanf("%s", command);
		if (strcmp(command, "add") == 0)
			add();
		else if (strcmp(command, "find") == 0)
			find();
		else if (strcmp(command, "status") == 0)
			status();
		else if (strcmp(command, "delete") == 0)
			remove();
		else if (strcmp(command, "exit") == 0)
			break;
	}
	return 0;
}

void add()
{
	char buf1[BUFFER_SIZE], buf2[BUFFER_SIZE];
	scanf("%s", buf1);
	scanf("%s", buf2);

	names[n] = _strdup(buf1);
	numbers[n] = _strdup(buf2);
}

void find()
{
	char buf[BUFFER_SIZE];
	scanf("%s", buf);

	int i;
	for (i = 0; i < n; i++) {
		if (strcmp(buf, names[i]) == 0) {
			printf("%s\n", numbers[i]);
			return;
		}
	}
	printf("No person named '%s' exists.\n", buf);
}			

void status() {
	int i;
	for (i = 0; i < n; i++)
		printf("%s  %s\n", names[i], numbers[i]);
	printf("Total %d persons.\n", n);
}

void remove()
{
	char buf[BUFFER_SIZE];
	scanf("%s", buf);

	int i;
	for (i = 0; i < n; i++) {
		if (strcmp(buf, names[i]) == 0) {
			names[i] = names[n - 1]; 
			numbers[i] = numbers[n - 1];
			n--; 
			printf("'%s' was deleted successfully.\n", buf);
			return;
		}
	}
	printf("No person named '%s' exists.\n", buf);
}