C + + practical syntax

String-to-char array conversion:

String str ("Please split this sentence into tokens");
char * CStr = new char [Str.length () +1];
strcpy (CStr, Str.c_str());

Quick Sort Qsort function

Need to include <stdlib.h> qsort

Features: Sorting using the quick sort routines

Usage: void qsort (void *base, int nelem, int width, int (*fcmp) (const void *,const void *));

Each parameter

1 array first address to sort

2 number of elements to be sorted in the array

3 space size of each element

4 pointers to functions

First, sort an array of type int

int cmp (const void *a, const void *b) {return * (int *) A-* (int *) b;} Qsort (Num,100,sizeof (num[0]), CMP);

Second, sort the array of char types (same as int type)

int cmp (const void *a, const void *b) {return * (char *) A-* (int *) b;} Qsort (Word,100,sizeof (word[0]), CMP);

Third, sort the array of double types (especially note)

int cmp (const void *a, const void *b) {return * (double *) a > * (double *) b? 1:-1;} Qsort (In,100,sizeof (in[0]), CMP);

Iv. Array of strings

int Compare_c (const void *a,const void *b) {return strcmp ((char*) A, (char*) b);} Qsort (F,n,16,compare_c);

C + + practical syntax