# How to Get Int31n Type Random Number in Golang?

Go language provides inbuilt support for generating random numbers of the specified type with the help of a math/rand package. This package implements pseudo-random number generators. These random numbers are generated by a source and this source produces a deterministic sequence of values every time when the program run. And if you want to random numbers for security-sensitive work, then use the crypto/rand package. You are allowed to generate a non-negative pseudo-random number in [0, n) of 31-bit integer n as an int32 type from the default source with the help of the Int31n() function provided by the math/rand package. So, you need to add a math/rand package in your program with the help of the import keyword to access the Int31() function. This method will panic if the value of n is <= 0. Syntax:
`func Int31n(n int32) int32`
Let us discuss this concept with the help of the given examples: Example 1:
 `// Golang program to illustrate ``// how to get a random number ``package main `` ` `import ( ``    ``"fmt"``    ``"math/rand"``) `` ` `// Main function ``func main() { `` ` `    ``// Finding random numbers of int31n type ``    ``// Using Int31n() function ``    ``res_1 := ``rand``.Int31n(2) ``    ``res_2 := ``rand``.Int31n(4) ``    ``res_3 := ``rand``.Int31n(1) `` ` `    ``// Displaying the result ``    ``fmt.Println(``"Random Number 1: "``, res_1) ``    ``fmt.Println(``"Random Number 2: "``, res_2) ``    ``fmt.Println(``"Random Number 3: "``, res_3) ``} `

Output:
```Random Number 1:  1
Random Number 2:  3
Random Number 3:  0
```
Example 2:
 `// Golang program to illustrate ``// how to get a random number ``package main `` ` `import ( ``    ``"fmt"``    ``"math/rand"``) `` ` `// Main function ``func main() { `` ` `    ``// If the value of this function ``    ``// is 0 or less than zero ``    ``// the this method will panics ``    ``res_1 := ``rand``.Int31n(0) ``    ``res_2 := ``rand``.Int31n(-1) `` ` `    ``// Displaying the result ``    ``fmt.Println(``"Random Number 1: "``, res_1) ``    ``fmt.Println(``"Random Number 2: "``, res_2) `` ` `} `

Output:
panic: invalid argument to Int31n goroutine 1 [running]: math/rand.(*Rand).Int31n(0x43e280, 0x0, 0x43e280, 0x460000) /usr/local/go/src/math/rand/rand.go:128 +0x180 math/rand.Int31n(…) /usr/local/go/src/math/rand/rand.go:324 main.main() /tmp/sandbox269134149/prog.go:16 +0x40

Previous
Next