不知道怎么想的

int main()
{
	string s;
	cin >> s;
	long long xbiao,xbei,dbiao;
	for(int i = 0;i<s.size();i++)
		if(s[i] == 'x')
		{
			xbiao = i;
			xbei = stoi(s.substr(0,xbiao));
		}
	for(int i = xbiao;i<=s.size();i++)
		if(s[i] == '=')
			dbiao = i;
	long long jia = stoi(s.substr(xbiao+1,dbiao)),zhi =stoi(s.substr(dbiao+1)),cha = zhi - jia,ans = cha*1.0/xbei;
}

scanf("%dx+%d=%d",&a,&b,%c);