错误提示：它是已删除的函数，求解答，谢谢！

Question

//程序片段意图：判断程序目录下是否存在input.txt文件，若不存在，则提示输入文件路径

//错误：函数调用出错input _ error(input) 中“input”被划出，提示调用函数是已删除函数 ==

 int input_error(fstream i){
    if (!i){
        cerr << endl << "Fail to open the file!" << endl << endl;
        return -1;
    }
    else
        return 0;
}
int main(){
    int n;
    fstream input("input.txt");
    if (input_error(input) == -1){
        fstream input;
        string filename;
        cout << "Please input the absolute path of the file:";
        getline(cin, filename, '\n');
        input.open(filename);
        if (input_error(input) == -1)return -1;
    };

以下为源代码，希望能够得到各位大神的解决，谢谢！

#include<iostream>
#include <iomanip>
#include<fstream>
#include<string>
using namespace std;
long long Fibo[90] = { 0 };
unsigned long long fibo(long n){
    if (n <= 1)
        return Fibo[n] = n;
    else if
        (Fibo[n] != 0) return Fibo[n];
    else
        return Fibo[n] = fibo(n - 1) + fibo(n - 2);
}
int input_error(fstream i){
    if (!i){
        cerr << endl << "Fail to open the file!" << endl << endl;
        return -1;
    }
    else
        return 0;
}
int main(){
    int n;
    fstream input("input.txt");
    if (input_error(input) == -1){
        fstream input;
        string filename;
        cout << "Please input the absolute path of the file:";
        getline(cin, filename, '\n');
        input.open(filename);
        if (input_error(input) == -1)return -1;
    };
    input >> n;
    input.close();
    if (n<0 || n>90){
        cout << endl << "The integer is illegal!" << endl << endl;
        return -1;
    }
    else
        cout << endl << "n: " << n << endl;
    cout << endl << "Result: " << fibo(n) << endl;
    cout << endl << "—————Process—————" << endl;
    for (int i = 0; i <= n; i++){
        cout << setw(2) << setfill('0') << i << ".....";
        cout << setw(19) << setfill('.') << Fibo[i] << endl;
    }
    cout << endl;
    return 0;
} 

再次感谢！
//：~

Answer 1

/*Fibonacci 1410729 许木胜 */
#include<iostream>
#include <iomanip>
#include<fstream>
#include<string>
using namespace std;
long long Fibo[90] = { 0 };
unsigned long long fibo(long n){
    if (n <= 1)
        return Fibo[n] = n;
    else if
        (Fibo[n] != 0) return Fibo[n];
    else
        return Fibo[n] = fibo(n - 1) + fibo(n - 2);
}
int input_error(fstream i){
    if (!i){
        cerr << endl << "Fail to open the file!" << endl << endl;
        return -1;
    }
    else
        return 0;
}
int main(){
    int n;
    fstream input("input.txt");
    if (input_error(input) == -1){
        fstream input;
        string filename;
        cout << "Please input the absolute path of the file:";
        getline(cin, filename, '\n');
        input.open(filename);
        if (input_error(input) == -1)return -1;
    };
    input >> n;
    input.close();
    if (n<0 || n>90){
        cout << endl << "The integer is illegal!" << endl << endl;
        return -1;
    }
    else
        cout << endl << "n: " << n << endl;
    cout << endl << "Result: " << fibo(n) << endl;
    cout << endl << "—————Process—————" << endl;
    for (int i = 0; i <= n; i++){
        cout << setw(2) << setfill('0') << i << ".....";
        cout << setw(19) << setfill('.') << Fibo[i] << endl;
    }
    cout << endl;
    return 0;
} 

以上才是源代码，第一次提问，错误请原谅= =