C언어 배열을 함수의 인자로 전달할때 쓰레기값이 중간에 들어가는거 질문드립니다.

int main() 
{	
	int num;
	int int_arr[5];
	char char_arr[MAX_LENGTH];
	char string_arr[MAX_STRING][MAX_LENGTH];
 
	for (num = 0; num < 5; num ++) {
		printf("%d번째 숫자를 입력하세요 : ", num);
		scanf("%d", &int_arr[num]);
	}
	for (num = 0; num < 5; num++) {
		printf("%d \t", int_arr[num]);
	}
	printf("\n");
 
	for (num = 0; num < 20; num ++) {
		printf("%d번째 문자를 입력하세요 : ", num);
		scanf("%s", &char_arr[num]);
	}
	select_sort_int(int_arr);
	select_sort_string(string_arr);
	return;
}

void select_sort_int(int *select_arr)
{
	int num1;
	int num2;
	int tmp;
	int *select_min;
 
	for (num1 = 0; num1 < 5; num1++) {
		printf("%d \t", select_arr[num1]);
	}
	printf("\n");
 
	printf("숫자 오름차순 선택정렬 : ");
	for (num1 = 0; num1 < 5; num1++) {
		select_min = &select_arr[num1];
		for (num2 = num1 + 1; num2 < 5; num2++) {
			if (*select_min > select_arr[num2]) {
				select_min = &select_arr[num2];
			}
		}
 
		if (select_arr[num1] != *select_min) {
			int_swap(&select_arr[num1], select_min);
		}
		printf("%d \t", select_arr[num1]);
	}
	printf("\n");
}
void select_sort_char(char *select_arr)
{
	int num1;
	int num2;
	char tmp;
	char *select_min;
 
	for (num1 = 0; num1 < MAX_LENGTH - 1; num1++) {
		select_min = &select_arr[num1];
		for (num2 = num1 + 1; num2 < MAX_LENGTH; num2++) {
			if (*select_min > select_arr[num2]) {
					select_min = &select_arr[num2];
			}
		}
 
		if (select_arr[num1] != *select_min) {
			char_swap(&select_arr[num1], select_min);
		}
	}
	printf("문자 오름차순 선택정렬 : %s\n", select_arr);
}