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invalid conversion from ‘const char*’ to ‘char’ 2 answers

#include<stdio.h>
#include<iostream>
#include<fstream>
#include<string.h>
using namespace std;

class base {
 public:
    int lookup(char c);
}; // class base

int base::lookup(char c)
{
    cout << c << endl;
} // base::lookup

int main() {
    base b;
    char c = "i";
    b.lookup(c);
} // main

При компиляции кода выше я получаю ошибку ниже:

g++ -c test.cpp test.cpp: In function ‘int main()’: test.cpp:20:10: error: invalid conversion from ‘const char*’ to ‘char’ [-fpermissive]