JuniorTheoryCommon

What does the program print?

package main

import "fmt"

func main() {
    m := map[string]int{"a": 0}
    v, ok := m["a"]
    w, ok2 := m["b"]
    fmt.Println(v, ok, w, ok2)
}

0 true 0 false

Expecting ok to be false for "a" because its value is 0: ok tells whether the key is in the map, and "a" is there.
Expecting a missing key to read as -1: a missing key reads as the zero value of the value type, which is 0 for int.

JuniorTheoryCommon

package main

import "fmt"

func main() {
    m := map[string]int{"a": 0}
    v, ok := m["a"]
    w, ok2 := m["b"]
    fmt.Println(v, ok, w, ok2)
}

0 true 0 false

Expecting ok to be false for "a" because its value is 0: ok tells whether the key is in the map, and "a" is there.
Expecting a missing key to read as -1: a missing key reads as the zero value of the value type, which is 0 for int.