经典排序算法---基数排序

//获取末尾数
int getmantissa(int num, int digits) {
	int temp = 1;
	for (int x = 0; x < digits - 1; ++x)
		temp *= 10;
	return (num / temp) % 10;
}

void radixsort(struct SQ_LIST *v) {
	int digit = 1;
	//获取位数
	int save[10][100001];
	for (int i = 0, p = 10; i < v->Length; ++i)
		while (v->elem[i].ID >= p) {
			p *= 10;
			++digit;
		}

	//初始化二位数组每行的首元
	for (int x = 0; x < 10; x++) {
		save[x][0] = 0;
	}

	//基数排序
	for (int i = 1; i <= digit; i++) {
		for (int x = 0; x < v->Length+1; ++x) {
			int mantissa = getmantissa(v->elem[x].ID, i);
			int index = ++save[mantissa][0];        //每行的首元存储每行数据量
			save[mantissa][index] = v->elem[x].ID;
		}

		//合并
		for (int i = 0, x = 0; i < 10; i++) {
			for (int j = 0; j < save[i][0]; ++j) 
				v->elem[x++].ID = save[i][j + 1];
			save[i][0] = 0;                      //重新初始化每行首单元                 
		}
	}
}