Convert string to char for ascii

Question

I want to ask for word from the user and then convert the word from string to char using 'strcpy'. Then I want to determine the sum of the ascii codes for all of the letters in the word.

However, I am having difficulties. I don't understand exactly how I can do that. This is what I have been able to do so far.

#include <iostream> #include <time.h> #include <stdlib.h> #include <string.h> using namespace std; int main() { string word; cout << "Enter word: "; getline(cin, word); /* char w[word]; strcpy(w,word.c_str()); int ('A'); cout<<char(65); */ return 0; }

The commented part is where I have been trying to do the converting. I copied the code from a worksheet. Even if it did work, I don't know how, and what it all means.

Thanks for your help.

You can't make a built-in array with a runtime-determined size. — Qaz
– Qaz, Commented Oct 20, 2013 at 23:13
This is my problem prompt: Ask the user for a word (use a textbox). Then determine the sum of the ascii codes for all of the letters in the word and state it in some label. You will need a string.h include and you will need to convert the word (that you get from the user) from string to char using ‘strcpy’ function. — user2877477
– user2877477, Commented Oct 20, 2013 at 23:18
If someone's telling you to use string.h in a C++ program, you need to find a better class. — Crowman
– Crowman, Commented Oct 20, 2013 at 23:24
Also, the idea that you need strcpy is pure stupidity. There's simply no need to make a copy, and even if there was, you can copy strings directly. — MSalters
– MSalters, Commented Oct 20, 2013 at 23:26

David G · Accepted Answer · 2013-10-21 03:06:27Z

char w[word]; strcpy(w, word.c_str());

char w[word] is incorrect. The square brackets is for the size, which must be a constant integral expression. word is of type std::string, so this makes neither logical nor practical sense. Maybe you meant it as:

char w = word;

But that still won't work because word is a string, not a character. The correct code in this case is:

char* w = new char[word.size() + 1];

That is, you allocate the memory for w using a char*. Then you use word.size() + 1 to initialize heap-allocated memory amounting to those bytes. Don't forget for the obligatory delete[] when you're finished using w:

delete[] w;

However, note that using raw pointers and explicit new is not needed in this case. Your code can easily be cleaned up into the following:

#include <numeric> int main () { std::string word; std::getline(std::cin, word); int sum = std::accumulate(word.begin(), word.end(), 0); /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ */ std::cout << "The sum is: " << sum << std::endl; }

@0x499602D2: It's for numerical algorithms, also has std::inner_product, adjacent_difference and partial_sum. C++11 adds iota.

Crowman · Accepted Answer · 2013-10-20 23:21:50Z

You don't need to use strcpy() (or use a char * at all, for that matter), but this'll do your counting using a char pointer:

#include <iostream> #include <string> int main() { std::string word; std::cout << "Enter word: "; std::cin >> word; const char * cword = word.c_str(); int ascii_total = 0; while ( *cword ) { ascii_total += *cword++; } std::cout << "Sum of ASCII values of characters is: "; std::cout << ascii_total << std::endl; return 0; }

Output:

paul@local:~/src/cpp/scratch$ ./asccount Enter word: ABC Sum of ASCII values of characters is: 198 paul@local:~/src/cpp/scratch$

If you really do want to use strcpy(), I'll leave it as an exercise to you to modify the above code.

Here's a better way to do it, just using std::string (and C++11, and obviously presuming your system uses the ASCII character set in the first place):

#include <iostream> #include <string> int main() { std::string word; std::cout << "Enter word: "; std::cin >> word; int ascii_total = 0; for ( auto s : word ) { ascii_total += s; } std::cout << "Sum of ASCII values of characters is: "; std::cout << ascii_total << std::endl; return 0; }

Thanks for your help. It would be EXTEREMELY helpful if you could do the modification of the code to strcpy(). I really do not know how to do it. Thank you very much anyway.

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