写两个函数
string LeftString(string s, int length)
{
return s.Substring(0, length);
}
string RightString(string s, int length)
{
if (length >= s.Length) return s;
return s.Substring(s.Length - length, length);
}
测试
string s = "123456";
string s1 = LeftString(s, 4); //<-- s1 = 1234
sring s2 = RightString(s, 4); //<-- s2 = 3456