C在循环内生成随机数

概述我想在循环内生成随机数,但结果总是相同的数字. 我做错了什么？谢谢. 码 #include <fstream>#include <ctime>#include <cstdlib>using namespace std;const char duom[] = "U1.txt";const char rez[] = "U1_rez.txt";void num_gen(int & x, 我想在循环内生成随机数,但结果总是相同的数字.
我做错了什么？谢谢.
码

#include <fstream>#include <ctime>#include <cstdlib>using namespace std;const char duom[] = "U1.txt";const char rez[] = "U1_rez.txt";voID num_gen(int & x,int & y);int main(){    srand(time(NulL));    int x,y;    ifstream fd(duom);    fd >> x >> y;    fd.close();    ofstream fr(rez);    for(int j = 1; j <= 4; j++){        num_gen(x,y);        fr << x << " + " << y << " = "<< x + y << endl;        fr << x << " - " << y << " = "<< x - y << endl;        fr << x << " * " << y << " = "<< x * y << endl;        fr << x << " / " << y << " = "<< x / y << endl;        fr << "************" << endl;    }    fr.close();    return 0;}voID num_gen(int & x,int & y){     x = 3 + (rand() % 10);     y = 3 + (rand() % 10);}

结果

4 8 = 12
4 – 8 = -4
4 * 8 = 32
4/8 = 0
************
4 9 = 13
4 – 9 = -5
4 * 9 = 36
4/9 = 0
************
9 11 = 20
9 – 11 = -2
9 * 11 = 99
9/11 = 0
************
12 8 = 20
12 – 8 = 4
12 * 8 = 96
12/8 = 1
************

解决方法 随着C 11/14的出现,你应该放弃使用srand&兰德&使用标题#include< random>中声明的更高效的随机数生成机器.以一个简单的例子说明： –

#include <iostream>#include <random>   // for default_random_engine & uniform_int_distribution<int>#include <chrono>   // to provIDe seed to the default_random_engineusing namespace std;default_random_engine dre (chrono::steady_clock::Now().time_since_epoch().count());     // provIDe seedint random (int lim){    uniform_int_distribution<int> uID {0,lim};   // help dre to generate nos from 0 to lim (lim included);    return uID(dre);    // pass dre as an argument to uID to generate the random no}int main(){    for (int i=0;i<10;++i)    cout<<random(10)<<" ";    return 0;}

上述代码的其中一项输出是： –

8 5 0 4 2 7 9 6 10 8

请参阅,数字从0到10不等.根据您所需的输出,在uniform_int_distribution中给出限制.这件事很少失败&你可以在更大的范围内生成随机数,而不必担心像你那样令人难以置信的输出.

总结

以上是内存溢出为你收集整理的C在循环内生成随机数全部内容，希望文章能够帮你解决C在循环内生成随机数所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。