#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 On Compiling above code I am getting below error :
g++ -c test.cpp test.cpp: In function ‘int main()’: test.cpp:20:10: error: invalid conversion from ‘const char*’ to ‘char’ [-fpermissive]
Try replacing
char c = "i"; with
char c = 'i'; 
"i" is not a character, it's a character array that basically decays to a pointer to the first element.
You almost certainly want 'i'.
Alternatively, you may actually want a lookup based on more than a single character, in which case you should be using "i" but the type in that case is const char * rather than just char, both when defining c and in the base::lookup() method.
However, if that were the case, I'd give serious thought to using the C++ std::string type rather than const char *. It may not be necessary, but using C++ strings may make your life a lot easier, depending on how much you want to manipulate the actual values.
"i" is a string literal, you probably wanted a char literal: 'i'.
String literals are null terminated arrays of const char (which are implicitly converted to char const* when used in that expression, hence the error).
char literals are just chars
