[Error] invalid conversion from 'const char*' to 'char' [-fpermissive]是哪里出错了？

//谁能帮我改下谢谢！
//17    32    D:\编程\c++\程序\72.cpp    [Error] invalid conversion from 'const char*' to 'char' [-fpermissive]
//还有18行和19行，都是一样的错误
#pragma GCC optimize(1)
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#include <iostream>
using namespace std;
const int N = 1e3 + 10;
string s[N];
int n;
int main() {
    cout << "请输入样例(输入Ctrl+Z结束):\n" ;
    int i = 1;
    while(getline(cin , s[i])) i++;
    for(int l = 1 ; l <= i - 1 ; l++) {
        for(int j = 1 ; j <= s[i].size() ; j++){
            if(s[l][j] == '\\') s[l][j] = "\\\\" ;else
            if(s[l][j] == '\"') s[l][j] = "\\\"" ;else
            if(s[l][j] == '\'') s[l][j] = "\\\'" ;
        }
    }
    system("cls");
    cout << "#include <bits/stdc++.h>\n" ;
    cout << "using namespace std;\n";
    cout << "int main(){\n" ;
    for(int k = 1 ; k <= i - 1 ; k++) cout << "    printf(\"" << s[k] << "\\n\");\n" ;
    cout << "return 0;" ; 
    cout << "}\n" ;
    system("pause");
    return 0;
}

难道“\”不能赋值吗？