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#include <iostream>

#include <cmath>

using namespace std;

int main ()

{

   // 数字定义

   short  s = 10;

   int    i = -1000;

   long   l = 100000;

   float  f = 230.47;

   double d = 200.374;

   // 数学运算

   cout << "sin(d) :" << sin(d) << endl;

   cout << "abs(i)  :" << abs(i) << endl;

   cout << "floor(d) :" << floor(d) << endl;

   cout << "sqrt(f) :" << sqrt(f) << endl;

   cout << "pow( d, 2) :" << pow(d, 2) << endl;

   return 0;

}

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#include <iostream>

#include <ctime>

#include <cstdlib>

using namespace std;

srand( (unsigned)time( NULL ) );

for(int i = 0; i < 10; i++ )

   {

      // 生成实际的随机数

      int j= rand();

      cout <<"随机数： " << j << endl;

   }

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#include<iostream>

#include<iomanip>

using namespace std;

int main(){

    double x=3.1415926;

    cout<<fixed<<setprecision(3)<<x<<endl;

    return 0;

}