某个范围内的随机数 c++
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Random number c++ in some range
提问by Abdul Samad
Possible Duplicate:
Generate Random numbers uniformly over entire range
可能的重复：
在整个范围内均匀地生成随机数
I want to generate the random number in c++ with in some range let say i want to have number between 25 and 63.
我想在 C++ 中生成某个范围内的随机数，比如说我想要 25 到 63 之间的数字。
How can i have that.
我怎么会有那个。
Thanks
谢谢
采纳答案by K-ballo
You can use the random functionality included within the additions to the standard library (TR1). Or you can use the same old technique that works in plain C:
您可以使用标准库 (TR1) 中添加的随机功能。或者您可以使用在普通 C 中工作的相同旧技术：
25 + ( std::rand() % ( 63 - 25 + 1 ) )
回答by Cubbi
Since nobody posted the modern C++ approach yet,
由于还没有人发布现代 C++ 方法，
#include <iostream>
#include <random>
int main()
{
std::random_device rd; // obtain a random number from hardware
std::mt19937 eng(rd()); // seed the generator
std::uniform_int_distribution<> distr(25, 63); // define the range
for(int n=0; n<40; ++n)
std::cout << distr(eng) << ' '; // generate numbers
}
回答by Nawaz
int random(int min, int max) //range : [min, max)
{
static bool first = true;
if (first)
{
srand( time(NULL) ); //seeding for the first time only!
first = false;
}
return min + rand() % (( max + 1 ) - min);
}
回答by Benjamin Lindley
int range = max - min + 1;
int num = rand() % range + min;
回答by Yurii Hohan
float RandomFloat(float min, float max)
{
float r = (float)rand() / (float)RAND_MAX;
return min + r * (max - min);
}
回答by Kiley Naro
Use the randfunction:
使用rand函数：
http://www.cplusplus.com/reference/clibrary/cstdlib/rand/
http://www.cplusplus.com/reference/clibrary/cstdlib/rand/
Quote:
引用：
A typical way to generate pseudo-random numbers in a determined range using rand is to use the modulo of the returned value by the range span and add the initial value of the range:
( value % 100 ) is in the range 0 to 99
( value % 100 + 1 ) is in the range 1 to 100
( value % 30 + 1985 ) is in the range 1985 to 2014
