<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script>
const num = Math.random()
console.log('random number')
console.log('0~10 random number', num * 10)
console.log('0~50 random number', num * 50)
console.log('')
console.log('random range number')
console.log('-5~5 : ', num * 10 - 5)
console.log('-25~25 : ', num * 50 -25)
console.log('')
console.log('random integer number')
console.log('-5~5 : ',Math.floor(num * 10 - 5))
console.log('-25~25 : ',Math.floor(num * 50 -25))
</script>
</head>
<body>
</body>
</html>### Generating a Base Random Number
- `const num = Math.random()` generates a base random floating-point number between 0 (inclusive) and 1 (exclusive).
### Scaling the Random Number
- The script first demonstrates how to scale this base number to different ranges:
- Multiplying `num` by 10 to get a range of 0 to just under 10.
- Multiplying `num` by 50 to get a range of 0 to just under 50.
### Adjusting the Range
- Next, the script shows how to adjust these scaled numbers to different ranges that include negative values:
- By subtracting 5 from `num * 10`, the range is shifted to -5 to just under 5.
- By subtracting 25 from `num * 50`, the range is shifted to -25 to just under 25.
### Generating Integer Values
- Finally, the script demonstrates converting these adjusted numbers into integers using `Math.floor`, which rounds down to the nearest whole number:
- `Math.floor(num * 10 - 5)` results in integer values from -5 to 4 (because the maximum value, just under 5, is floored to 4).
- `Math.floor(num * 50 -25)` results in integer values from -25 to 24 (because the maximum value, just under 25, is floored to 24).
### Understanding the Output
The script logs all these calculations to the console, showing the versatility of `Math.random` for generating random numbers in JavaScript:
- **Random floating-point ranges**: It first prints out the base random number scaled to 0-10 and 0-50 ranges.
- **Random floating-point numbers within negative to positive ranges**: It shows adjusted ranges, such as -5 to 5 and -25 to 25, still as floating-point numbers.
- **Random integer ranges**: It finally demonstrates generating integers within specified ranges, including negative values, by applying `Math.floor` to the previously adjusted numbers.
This approach of manipulating the output of `Math.random()` is useful for a wide variety of applications where random numbers within specific ranges are needed, including games, simulations, and randomized data generation.
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