algorithm

一、algorithm

min(a, b)

max(a,b)

string str

reverse(str.begin(), str.end());

swap(a, b)

vector v

sort(v.begin(), v.end(),less) 升序

sort(v.begin(), v.end(),lgreater) 降序

关于字符串和字符的大小写转换

string s = "r74k";

char p[] = "r74k";

transform(s.begin(),s.end(),s.begin(),toupper);

transform(p,p+4,toupper);

char a = toupper('a');

char b = tolower('A');