C++ 生成随机数组 无输出

Question

屏幕上没有输出数组的内容。

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

int main() {
    //决定数组长度
    unsigned short length;
    srand((unsigned)time(NULL));
    length = (unsigned)rand() % 128;
    cout << "数组长度:" << length << "\n" << endl;
    //创建数组
    int *array = (int *)malloc(sizeof(int) * length);
    //发牌
    {
        int *operating;
        operating = array;
        int i;
        cout << "数组:" << endl;
        for (i = 0; i++; i < length) {
            srand((unsigned)time(NULL));
            *operating = (unsigned)rand();
            cout << "\b" << *operating << "\u0020" << endl;
            operating++;
        }
    }
    return 0;
}

Answer 1

（1）for循环的第二个表达式和第三个表达式写反了。i<lengh在中间作为循环条件，i++在最后。

for (i = 0; i<length; i++)

（2）for循环中没必要在执行一次srand()，如果不改变随机数种子，一个代码中只需要调用一次srand()就可以了

代码：

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

int main() {
    //决定数组长度
    unsigned short length;
    srand((unsigned)time(NULL));
    length = (unsigned)rand() % 128;
    cout << "数组长度:" << length << "\n" << endl;
    //创建数组
    int* array = (int*)malloc(sizeof(int) * length);
    //发牌
    {
        int* operating;
        operating = array;
        int i;
        cout << "数组:" << endl;
        for (i = 0; i<length; i++) { //修改1 
            //srand((unsigned)time(NULL));  修改2，这一句不需要，一个代码中，随机数种子设置一次就可以了
            *operating = (unsigned)rand();
            cout << "\b" << *operating << "\u0020" << endl;
            operating++;
        }
    }
    return 0;
}