Using cout to print the entire contents of a character array

Start with something simple:

char c_array[3]; c_array[0] = 'a'; c_array[1] = 'b'; c_array[2] = 'c'; for(int i=0 ; i<3 ; ++i) { cout << c_array[i]; } cout << endl; 

Do not go farther until you understand that much perfectly. Now notice that if you null-terminate the array, you can pass the whole thing to cout, and operator<< will know when to stop:

char c_array[4]; c_array[0] = 'a'; c_array[1] = 'b'; c_array[2] = 'c'; c_array[3] = 0; cout << c_array << endl; 

You cannot do that with arrays of most other types. Now notice that you can assign a char[] this way, and it will be null-terminated:

char c_array[20] = "abc"; cout << c_array << endl; 

You can even omit the size of the array, and the compiler will infer it:

char c_array[] = "abc"; // this is a char[4]; cout << c_array << endl; 

There are a couple of different ways to read user input into an array, but it sounds as if you know that already, and this answer is getting long.

Writing each character individually using operator<<(char) is inefficient.

Converting to an std::string using the (const char*, size_t) constructor, and writing that using operator<<(const std::string&) is also inefficient.

The proper way is simply to use http://en.cppreference.com/w/cpp/io/basic_ostream/write

PS: Note that your code is not valid C++. char name[] is basically synonymous with char* name and doesn't know its length (and there's no .length() on it too). And your nameArray is not initialized. Sized, yes; initialized, no. You're missing a std::copy or strncpy call to copy the content of fullName into nameArray.

printf("%s", nameArray); 

just works!

This is a bit <O/T> from the OP, but I googled "c++ print std::array char" and this was the top hit, yet none of these answers cover how to do this with std::array<char, >. You can't apply the operator<< directly to the array, you need to access its .data() pointer first:

#include <string> #include <iostream> #include <array> int main() { // a direct initialization example. Remember, need string legnth+1 for // a NUL terminator std::array<char, 6> bar{"hello"}; // print to std::out using operator<< and the .data() ptr access std::cout << bar.data() << std::endl; // extra example copying the contents of a string to an array. std::string foo("how are you?"); // {} initializes it to 0, giving us guaranteed NUL termination std::array<char, 24> tar{}; // copy string to array, std::min ensures we won't overrun foo.copy(tar.data(), std::min(foo.length(), tar.size()-1)); std::cout << tar.data() << std::endl; return 0; } 

Output:

hello how are you? 

Demonstration

For my problem, my program was looking for a command line parameter. Since I did not provide the parameter, so it throws terminate called after throwing an instance of std::logic_error what(): basic_string::_S_construct null not valid

I hope this gives you some insight on how to figure your problem.

Here's a generic way to do it.

Run example

// write out any c style char array to an output stream #include <iostream> #include <string.h> void write_char_array(std::ostream& os, const char* string) { // faster than an ostream_iterator and std::copy os.write(string, strlen(string)); } int main() { const char question[] = "What is your name? "; const char* answer = "Bob"; write_char_array(std::cout, question); write_char_array(std::cout, answer); } 

Output:

What is your name? Bob