Custom addition and subtraction of two strings

#include <iostream>
using namespace std;
int strSub(char* p1, char* p2, int* sub);
int main()
{
	int sub[20];
	char s1[20], s2[20];
	cout << "请输入第一个字符串：" << endl;
	cin >> s1;
	cout << "请输入第二个字符串：" << endl;
	cin >> s2;
	strSub(s1, s2, sub);
	return 0;
}
int strSub(char* p1, char* p2, int* sub)
{
	int r, t;
	for (; *p1 == *p2 && (*p1 != '\0' || *p2 != '\0'); p1++, p2++);
	r = *p1 - *p2;
	r == 0 ? t = 0 : t = *p1 - *p2;
	return t;
	/*int i,n;
	for (i = 0; p1[i] != '\0' || p2[i] != '\0'; i++);
	sub[i] = p1[i] - p2[i];
	n=i;
	cout << "结果是：" << endl;
	for (i = 0; i < n; i++)

	cout << sub[i] << ' ';
	return 0;*/
}