快速排序

void QuickSort(int a[], int length){if(a == NULL || length <= 1)return;int start = 0, end = length - 1;int val = a[0];while(start < end){for(;start<end;--end){if(a[end]<val){a[start] = a[end];break;}}for(;start<end;++start){if(a[start]>val){a[end] = a[start];break;}}}a[start] = val;QuickSort(a, start);QuickSort(a+start+1, length-start-1);}