I want to fill a vector with the letters of the alphabet. So I wrote the following:
#include <iostream>
#include <algorithm>
#include <vector>
#include <iterator>
char i='a';
char f(){return i++;};
int main()
{
std::vector<char> lol(24);
std::generate_n(lol.begin(),lol.size(),f);
std::copy(lol.begin(),lol.end(),std::ostream_iterator<int>(std::cout,","));
}
But std::copy prints 97,98,99... the ASCII codes of the letters. How can I fix this?
Your ostream_iterator is <int> instead of <char> - Try changing it to <char>
change the template specialization to char :std::copy(lol.begin(),lol.end(),std::ostream_iterator<char>(std::cout,","));
Related
Currently going thru a c++ course.
I had to create a word cipher using the strings: alphabet and key.
to cipher an inputted word with less code as possible I created this solution that gives the error:
no matching function for call to std::basic_string<char>::find(std::string&, int&, int)
I don't know how to solve it, neither do I know if my idea would work at all, would LOVE some help.
Thanks for your attention :)
#include <iostream>
#include <cstring>
#include <string>
using namespace std;
int main() {
string alphabet {"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"};
string key {"XZNLWEBGJHQDYVTKFUOMPCIASRxznlwebgjhqdyvtkfuompciasr"};
string word_to_encrypt {};
getline (cin,word_to_encrypt);
for (int i=0;i<word_to_encrypt.size;i++){
word_to_encrypt.replace (i,1,key,(alphabet.find(word_to_encrypt,i,1)),1);
}
cout<< word_to_encrypt;
}
Two problems:
First size is a function and not a variable. Therefore you need size().
Secondly std::string::find() has no overload which takes a std::string and two ints: https://en.cppreference.com/w/cpp/string/basic_string/find , but you can use the overload which takes a CharT instead by adding .c_str() or .data().
This compiles at least:
#include <iostream>
#include <cstring>
#include <string>
using namespace std;
int main() {
string alphabet {"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"};
string key {"XZNLWEBGJHQDYVTKFUOMPCIASRxznlwebgjhqdyvtkfuompciasr"};
string word_to_encrypt {};
getline (cin,word_to_encrypt);
for (int i=0;i<word_to_encrypt.size();i++){
word_to_encrypt.replace(i, 1, key, (
alphabet.find(word_to_encrypt.c_str(), i, 1)),1);
}
cout<< word_to_encrypt;
}
I want to have a dynamic structure which I could iterate on, there will be unknown number of entries and known number of strings for each entry. I thought that vector of array of strings could be the way, however I get error while compiling this:
vector< array<string, 5> >
error: invalid use of incomplete type 'struct std::array<std::basic_string<char>, 5u>'
What am I doing wrong? and if this is kind of the way - how would I add/get values to/from this structure?
Did you include all these three headers?
#include <vector>
#include <array>
#include <string>
This compiles just fine:
#include <vector>
#include <array>
#include <string>
int main(int argc, char const *argv[])
{
std::vector<std::array<std::string, 5> > myVec;
return 0;
}
I am experimenting with CGI in C++. I know that there are libraries which handle basic stuff, but in order to know whats going on under the hood i have been trying to parse the stdin using string datatype ---> tokenize using '= and &' then push_back into a vector. at the latter step, i am receiving segmentation fault. given below is the program where i am using cin>> to obtain user input and so on ..
#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <vector>
#include <algorithm>
#include <string.h>
using namespace std;
int main()
{
vector <string> stuff(0);
vector<string>::iterator it;
char* bufferchar;
string buffer;
char str[size];
cout<<"Content-type: text/html\n\n"
<<"<html>"
<<"<head>"
<<"<title>CGI SCRIPT</title>"
<<"</head>"
<<"<body>"
fgets(str,20,stdin); //20 is expect size of content from html form
puts(str);
cout<<"<p>Now to break this guy apart";
int x=0;
bufferchar = strtok(str,"&=");
buffer+=bufferchar;
stuff.push_back(buffer);
while(bufferchar!=NULL){
cout<<bufferchar<<'\n'<<'\n';
bufferchar=strtok(NULL,"&=");
buffer+=bufferchar;
stuff.push_back(buffer);
}
cout<<"<br>ok does the vector iterate ?";
for (it=stuff.begin();it!=stuff.end();++it){
cout<<*it;
cout<<"<br> ok man, next <br><br>";
}
cout<<"</body>";
cout<<"</html>";
}
This is part of the code (header and the main part):
#include <iostream>
#include <sstream>
#include <string>
#include <gl\GL.h>
#include <gl\GLU.h>
#include <glut.h>
#include <RassHost.h>
#include <api\iomap.h>
#include <api\iotrans.h>
#include <api\cgeometry.h>
#include <vector>
using namespace std;
int main()
{
cout << "Enter IP: " << endl;
getline(cin, server_ip);
enum(KEY_L = 'A', KEY_R = 'D', KEY_RUN = 'WW', KEY_JUMP='SPACE');
typedef OBJECT_3D_SYS_TYPES_NUM OBJECT3D_RCN_TYPE;
OBJECT3D_RCN_TYPE _psyObjects[][] = getPsyhicsPartObjects();
vector<OBJECT3D_RCN_TYPE> _objects;
//I would like to load _psyObjects[][] into vector<OBJECT3D_RCN_TYPE> _objects;
Server::StartGame(Server::getIP(), 8888, "-r run", false);
system("pause");
return 0;
}
Is it possible to copy _psyObjects values into vector<OBJECT3D_RCN_TYPE>?
I want to control the multidimensional array with vector api, if it is possible.
Thanks!
You'll need to create a vector of vectors:
vector< vector<OBJECT3D_RCN_TYPE> > _objects;
Then just fill it like a normal vector.
I'd post more code, but you need to know the dimensions of the array, and I can't see those from the code.
You could also use a Boost::multi_array. It's api is like std::vector's, but possibly similar enough to meet your needs.
I'm trying to use a vector of strings in my code instead of an array of strings but apparently I miss some detail in the declaration of the vector. Using the following code, I get this error: ‘vector’ was not declared in this scope
// Try to implement a vector of string elements
#include<iostream>
using namespace std;
int main() {
const int MAX_ITEMS = 10;
vector<string> my_vector(MAX_ITEMS);
return 0;
}
How should I correctly declare the vector?
You should add these includes:
#include <vector>
#include <string>
You have to include the header:
#include <vector>
#include <string>
You need:
#include <vector>