C++ 在两个浮点数之间生成随机浮点数
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Generate random float between two floats
提问by Maks
I know this is a rather simple question, but I'm just not too good at maths.
我知道这是一个相当简单的问题，但我只是不太擅长数学。
I know how to generate a random float between 0 and 1:
我知道如何生成 0 到 1 之间的随机浮点数：
float random = ((float) rand()) / (float) RAND_MAX;
- But what, if I want a function that given a range of two floats, returns a pseudorandom float in that range?
- 但是，如果我想要一个给出两个浮点数范围的函数，返回该范围内的伪随机浮点数呢？
Example:
例子：
RandomFloat( 0.78, 4.5 ); //Could return 2.4124, 0.99, 4.1, etc.
回答by Wim
float RandomFloat(float a, float b) {
float random = ((float) rand()) / (float) RAND_MAX;
float diff = b - a;
float r = random * diff;
return a + r;
}
This works by returning aplus something, where somethingis between 0 and b-awhich makes the end result lie in between aand b.
这通过返回aplus 的东西来工作，其中一些东西介于 0 之间，b-a这使得最终结果介于a和之间b。
回答by Doug T.
float RandomFloat(float min, float max)
{
// this function assumes max > min, you may want
// more robust error checking for a non-debug build
assert(max > min);
float random = ((float) rand()) / (float) RAND_MAX;
// generate (in your case) a float between 0 and (4.5-.78)
// then add .78, giving you a float between .78 and 4.5
float range = max - min;
return (random*range) + min;
}
回答by Benjamin
Random between 2 float :
2个浮动之间的随机数：
float random_between_two_int(float min, float max)
{
return (min + 1) + (((float) rand()) / (float) RAND_MAX) * (max - (min + 1));
}
Random between 2 int :
2 int 之间的随机数：
int random_between_two_int(float min, float max)
{
return rand() % (max - min) + min + 1;
}
回答by Dr. Debasish Jana
Suppose, you have MIN_RAND and MAX_RAND defining the ranges, then you can have the following:
假设你有 MIN_RAND 和 MAX_RAND 定义范围，那么你可以有以下内容：
const float MIN_RAND = 2.0, MAX_RAND = 6.0;
const float range = MAX_RAND - MIN_RAND;
float random = range * ((((float) rand()) / (float) RAND_MAX)) + MIN_RAND ;
This will provide you the number scaled to your preferred range. MIN_RAND, MAX_RAND can be any value, like say 2.5, 6.6 So, the function could be as:
这将为您提供缩放到您首选范围的数字。MIN_RAND, MAX_RAND 可以是任何值，比如 2.5, 6.6 所以，函数可以是：
float RandomFloat(float min, float max) {
return (max - min) * ((((float) rand()) / (float) RAND_MAX)) + min ;
}
