Tidak Bisa Login Menggunakan Akun Ke 2 Yg Sudah didaftarkan

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

char user[5][100], pass[5][25];
char logUser[25], logPass[25], New[25];
char again,change;
int data=0,i,arr,x,choose;


int main(){
    regis :
    if(data==5)
        {
            printf("\nAccount Has Been Full\n\n");
            goto login;
        }
            fflush(stdin);
            printf("Registration :\n");
            printf("Enter The Username = ");
            gets(user[data]);
            printf("Enter The Password = ");
            gets(pass[data]);
            data++;
            printf("Register Again? [Y/N] ");
            scanf("%c", &again);
            if(again=='y' || again=='Y')
            {
                printf("\n");
                goto regis;
            } else if(again == 'N' || again == 'n')
            {
                printf("\n");
                goto login;
            }
    login :
    fflush(stdin);
    printf("Login :\n");
    printf("Enter The Username = ");
    gets(logUser);
    printf("Enter The Password = ");
    gets(logPass);

    for(i=1;i<=data;i++){
        switch(i)
        {
        case 1:
            arr=0;
            if(strcmp(logUser, user[arr])==0 && strcmp(logPass, pass[arr])==0){
                printf("\nLogin Successful\n");
                goto update;
            } else {
                printf("Login Failed\n");
                goto login;
            }
            break;
        case 2:
            arr=1;
            if(strcmp(logUser, user[arr])==0 && strcmp(logPass, pass[arr])==0){
                printf("\nLogin Successful\n");
                goto update;
            } else {
                printf("Login Failed\n");
                goto login;
            }
            break;
        case 3:
            arr=2;
            if(strcmp(logUser, user[arr])==0 && strcmp(logPass, pass[arr])==0){
                printf("\nLogin Successful\n");
                goto update;
            } else {
                printf("Login Failed\n");
                goto login;
            }
            break;
        case 4:
            arr=3;
            if(strcmp(logUser, user[arr])==0 && strcmp(logPass, pass[arr])==0){
                printf("\nLogin Successful\n");
                goto update;
            } else {
                printf("Login Failed\n");
                goto login;
            }
            break;
        case 5:
            arr=4;
            if(strcmp(logUser, user[arr])==0 && strcmp(logPass, pass[arr])==0){
                printf("\nLogin Successful\n");
                goto update;
            } else {
                printf("Login Failed\n");
                goto login;
            }
            break;
        default:
            printf("Login Failed\n");
            goto login;
            break;
        }
    }
    update :
    printf("Change The Password [Y/N] ");
    scanf("%c", &change);
    printf("\n");
    if(change=='Y' || change=='y'){
        fflush(stdin);
        printf("Username = %s\nPassword = %s\n", user[x], pass[x]);
        printf("New Password = ");
        gets(New);
        strcpy(pass[x], New);
        goto list;
    }else if(change=='N' || change=='n'){
        printf("\n~~~Thank You~~~\n");
        exit(1);
    }
    list :
    printf("\n\n");
    for(i=1;i<=data;i++){
        if(user[i-1]!='\0' && pass[i-1]!='\0'){
            printf("%d. Username = %s, Password = %s\n",i,user[i-1],pass[i-1]);
        }
    }
    printf("\n1.LOGIN \n2.LOGOUT\n");
    printf("\nChoose: ");
    scanf("%d",&choose);
    if(choose==1){
        goto login;
    }else if(choose==2){
        printf("\n~~~Thank You~~~\n");
        exit(2);
    }
    return 0;
}