STL: <algorithm>中 sort()

/*
* void sort(Randomlt first, Randomlt last)
* void sort(Randomlt first, Randomlt last, Compare comp)
* sort fist to last by ZiDian sort.
* the Compare comp is a help funtion
*/

#include <algorithm>
#include <iostream>
#include <string.h>
using namespace std;

int cmp(char , char);

int main() {
//sotr(Randomlt first, Randomlt last);
char str1[] = "alsdfjekxALSDFJEK";
int n;

n = strlen(str1);

cout<<str1<<endl;
sort(str1, str1 + n);
cout<<str1<<endl;

//sort(Randomlt first, Randomlt last, Compare comp);
char str2[] = "AkasdSKDFNslkdaKf";
n = strlen(str2);
cout<<"A a"<<cmp('A', 'a')<<endl;
cout<<"Z b"<<cmp('Z', 'b')<<endl;
cout<<"Z Z"<<cmp('Z', 'Z')<<endl;
cout<<str2<<endl;
sort(str2, str2 + n, cmp);
cout<<str2<<endl;

return 0;
}

int cmp(char a, char b) {

if (tolower(a) == tolower(b)) {
return a < b;
}else {
return tolower(a) < tolower(b);
}
}