Java problems calling an array

Question

Hello, could someone tell me why the program is not finding the array I (I will signal in the code below :

Error:

error: cannot find Symbol R+= I[P0]; Symbol: variable I Location: class matematica 1 error

class Matematica {
    public static void main (String args[]) {

    Scanner ler = new Scanner(System.in);

    int T = ler.nextInt();

    for(int SN=0 ; SN < T ; SN++){
        int N = ler.nextInt();
        int I[]=new int [N];            
        I[SN]=ler.nextInt();
    }              

    int Q = ler.nextInt();

    for(int SQ=0 ; SQ < Q ; SQ++) {
        int P [] = new int[2];
        P[0] = ler.nextInt();
        P[1] = ler.nextInt();

        while(P[0] <= P[1]) {

            int P0=P[0];
            int R = 0;
            R+= I[P0]; // O erro está nessa linha
            if(P[0] == P[1])          
                System.out.printf("%d",R);

            P[0]++; 
        }
    }     
}    

Answer 1

This is because in this line you are creating the variable I inside the block for, thus:

for(int SN=0 ; SN < T ; SN++){
    int N = ler.nextInt();
    int I[]=new int [N];            
    I[SN]=ler.nextInt();
} 

Thus, the variable I will only exist within this code block.

One way to solve would be to declare the variable above the for

int I[] = new int[0];        
...
for(int SN=0;SN<T;SN++){
    ...
    I = new int [N]; 

---

Council

Always use descriptive names for your variables, this makes the code stay extremely simplest to understand. If you are going to declare a variable to represent a client’s name, use String nomeCliente = "Joaquim";. That way you (and anyone) will understand what this variable does (practically) just by looking at her name.