how to use map in Go - loops

Question

I want to make a simple program to count debt installments. The requirements are:
Input the debt value
Input how long the installments
The first half of the installment bank interest is 11% and the rest are 8%
Must use maps
Here's my code
package main
import "fmt"
func main() {
fmt.Print("Input the debt value : ")
var debt int
fmt.Scanln(&debt)
fmt.Print("Input how long the installments : ")
var installment int
fmt.Scanln(&installment)
fmt.Println("====================================================")
fmt.Println("Total debt : ", debt)
fmt.Println("Installments : ", installment)
fmt.Println("====================================================")
var firstHalf = installment / 2
var pay int
for i := 1; i <= installment; i++ {
value := map[string]int{
"month": i,
"payment": pay,
}
if i <= firstHalf {
pay = (debt / installment) + (debt * 11 / 100)
fmt.Println(value["month"],"Installment with bank interest (11%) is", value["payment"])
} else {
pay = (debt / installment) + (debt * 8 / 100)
fmt.Println(value["month"],"Installment with bank interest (8%) is", value["payment"])
}
}
}
If I run the code and for example :
The debt is 10.000.000
The installments are 7 months
Here's the output :
1 Installment with bank interest (11%) is 0
2 Installment with bank interest (11%) is 2528571
3 Installment with bank interest (11%) is 2528571
4 Installment with bank interest (8%) is 2528571
5 Installment with bank interest (8%) is 2228571
6 Installment with bank interest (8%) is 2228571
7 Installment with bank interest (8%) is 2228571
I don't know why the first index is always 0, even the next calculation is right. So, I guess that either I am using the wrong syntax or I am trying to do something that can not be done. Maybe most likely experienced people will see right away what is wrong.

Answer 1

if i <= firstHalf {
pay = (debt / installment) + (debt * 11 / 100)
value["payment"] = pay
fmt.Println(value["month"],"Installment with bank interest (11%) is",
value["payment"])
} else {
pay = (debt / installment) + (debt * 8 / 100)
value["payment"] = pay
fmt.Println(value["month"],"Installment with bank interest (8%) is",
value["payment"])
}

Answer 2

It is printing the the payment value of map as 0 because it is assigned with pay which has no value initially.You can fix this by declaring the map beneath the if else condition and then print your values,here is the modified code for the same logic:
package main
import "fmt"
func main() {
fmt.Print("Input the debt value : ")
var debt int
fmt.Scanln(&debt)
fmt.Print("Input how long the installments : ")
var installment int
fmt.Scanln(&installment)
fmt.Println("====================================================")
fmt.Println("Total debt : ", debt)
fmt.Println("Installments : ", installment)
fmt.Println("====================================================")
var firstHalf = installment / 2
var pay int
for i := 1; i <= installment; i++ {
if i <= firstHalf {
pay = (debt / installment) + (debt * 11 / 100)
} else {
pay = (debt / installment) + (debt * 8 / 100)
}
value := map[string]int{
"month": i,
"payment": pay,
}
if i <= firstHalf {
fmt.Println(value["month"], "Installment with bank interest (11%) is", value["payment"])
} else {
fmt.Println(value["month"], "Installment with bank interest (8%) is", value["payment"])
}
}
}
Output:
Input the debt value : 1000
Input how long the installments : 5
====================================================
Total debt : 1000
Installments : 5
====================================================
1 Installment with bank interest (11%) is 310
2 Installment with bank interest (11%) is 310
3 Installment with bank interest (8%) is 280
4 Installment with bank interest (8%) is 280
5 Installment with bank interest (8%) is 280