I have a function in C++ that have a value in std::string type and would like to convert it to String^.
void(String ^outValue)
{
std::string str("Hello World");
outValue = str;
}
From MSDN:
#include <string>
#include <iostream>
using namespace System;
using namespace std;
int main() {
string str = "test";
String^ newSystemString = gcnew String(str.c_str());
}
http://msdn.microsoft.com/en-us/library/ms235219.aspx
Googling reveals marshal_as (untested):
// marshal_as_test.cpp
// compile with: /clr
#include <stdlib.h>
#include <string>
#include <msclr\marshal_cppstd.h>
using namespace System;
using namespace msclr::interop;
int main() {
std::string message = "Test String to Marshal";
String^ result;
result = marshal_as<String^>( message );
return 0;
}
Also see Overview of Marshaling.
As far as I got it, at least the marshal_as approach (not sure about gcnew String) will lead to non ASCII UTF-8 characters in the std::string to be broken.
Based on what I've found on https://bytes.com/topic/c-sharp/answers/725734-utf-8-std-string-system-string I've build this solution which seems to work for me at least with German diacritics:
System::String^ StdStringToUTF16(std::string s)
{
cli::array<System::Byte>^ a = gcnew cli::array<System::Byte>(s.length());
int i = s.length();
while (i-- > 0)
{
a[i] = s[i];
}
return System::Text::Encoding::UTF8->GetString(a);
}
Related
#include <iostream>
using namespace std;
int main() {
char word[10]="php";
char word1[10]="php";
if(word==word1){
cout<<"word = word1"<<endl;
}
return 0;
}
I don't know how to compare two char strings to check they are equal. My current code is not working.
Use strcmp.
#include <cstring>
// ...
if(std::strcmp(word, wordl) == 0) {
// ...
}
Use std::string objects instead:
#include <iostream>
#include <string>
using namespace std;
int main() {
string word="php";
string word1="php";
if(word==word1){
cout<<"word = word1"<<endl;
}
return 0;
}
To justify c++ tag you'd probably want to declare word and word1 as std::string. To compare them as is you need
if(!strcmp(word,word1)) {
word and word1 in your submitted code are pointers. So when you code:
word==word1
you are comparing two memory addresses (which isn't what you want), not the c-strings they point to.
#include <iostream>
**#include <string>** //You need this lib too
using namespace std;
int main()
{
char word[10]="php";
char word1[10]="php";
**if(strcmp(word,word1)==0)** *//if you want to validate if they are the same string*
cout<<"word = word1"<<endl;
*//or*
**if(strcmp(word,word1)!=0)** *//if you want to validate if they're different*
cout<<"word != word1"<<endl;
return 0;``
}
/* I thought of doing in this way, but it invalid.
so any help will be appreciated. */
#include <cstdlib>
#include <iostream>
#include <string>
using namespace std;
int main()
{
string name = "Karma";
string greet = "How was your day?";
string sums = name + greet;
system("say %s", sums) // not working
// system("say sums") not working
return 0;
}
You can use:
system(("say" + sums).c_str())
Instead of:
system("say %s", sums)
I am trying to reverse a string. Can someone explain me why this is giving me segmentation fault?
#include <iostream>
#include <string>
using namespace std;
int main(){
string str,rstr;
int len=str.length(),i=0;
cin>>str;
while(str[i]!='\0'){
rstr[--len]=str[i++];
}
rstr[str.length()]='\0';
cout<<rstr;
return 0;
}
P.S.: Need to reverse it without using library functions.
If you want to go the way you are doing it, for practice purposes, try this changes and start from there
#include <iostream>
#include <string>
using namespace std;
int main(){
string str,rstr;
cin>>str; // --- Moved this line up
rstr = str; // --- Added this line
int len=str.length(),i=0;
while(str[i]!='\0'){
rstr[--len]=str[i++];
}
rstr[str.length()]='\0';
cout<<rstr;
return 0;
}
Or just use reverse iterator
std::string s = "Hello";
std::string r(s.rbegin(), s.rend());
str is nothing but a declared string here:
int len=str.length(),i=0;
So you can't do str.length()
Do something like:
#include <iostream>
#include <string>
using namespace std;
int main(){
string str,rstr;
int len,i=0;
cin>>str;
len = str.length();
while(str[i]!='\0'){
rstr[i++]=str[--len];
}
rstr[str.length()]='\0';
cout<<rstr;
return 0;
}
I'm trying to read text from a .log file. I originally have it working a a windows console application but I'm now trying to make a GUI version using MFC. The problem is when i set the while loop as while(file.good()), it completely skips the loop and I'm not sure why because there are no errors with file.open()
void Conversion::toXml(CString openPath, CString savePath)
{
CString null("/0");
int c = openPath.GetLength(),q=0;
while(q<c)
{
if(openPath[q] == '\\')
{
openPath.Insert(q,'\\');
q++;
}
q++;
}
CStringA charstr(openPath);
const char* oPath((const char *) charstr);
CStringA charstr2(savePath);
const char* sPath((const char *) charstr2);
ifstream openFile;
ofstream savedFile(sPath);
string recText = "";
string temp;
openFile.open(oPath);
while(openFile.good())
{
getline(openFile,temp);
recText = recText + temp;
}
smaller version(should compile)
#include <iostream>
#include <fstream>
#include <string>
#include "stdio.h"
#include <windows.h>
#include <algorithm>
#include <atlstr.h>
using namespace std;
int main()
{
string recText = "";
string temp;
CString path = "C:\\Users\\name\\Desktop\\2012-08-281.log";
CStringA charstr(path);
const char* oPath((const char *) charstr);
ifstream xmlDoc (oPath);
ofstream finished ("C:\\Users\\name\\Documents\\example3.xml");
while(xmlDoc.good())
{
getline(xmlDoc,temp);
recText = recText + temp;
}
finished<<recText<<endl;
return 0;
}
The problem might be that you try to escape the backslash when you don't need it, adding unnecessary backslashes in the path. Escaping backslashes is only needed for string literals. It might be that Windows doesn't like paths with multiple consecutive backslashes.
#include <iostream>
using namespace std;
int main() {
char word[10]="php";
char word1[10]="php";
if(word==word1){
cout<<"word = word1"<<endl;
}
return 0;
}
I don't know how to compare two char strings to check they are equal. My current code is not working.
Use strcmp.
#include <cstring>
// ...
if(std::strcmp(word, wordl) == 0) {
// ...
}
Use std::string objects instead:
#include <iostream>
#include <string>
using namespace std;
int main() {
string word="php";
string word1="php";
if(word==word1){
cout<<"word = word1"<<endl;
}
return 0;
}
To justify c++ tag you'd probably want to declare word and word1 as std::string. To compare them as is you need
if(!strcmp(word,word1)) {
word and word1 in your submitted code are pointers. So when you code:
word==word1
you are comparing two memory addresses (which isn't what you want), not the c-strings they point to.
#include <iostream>
**#include <string>** //You need this lib too
using namespace std;
int main()
{
char word[10]="php";
char word1[10]="php";
**if(strcmp(word,word1)==0)** *//if you want to validate if they are the same string*
cout<<"word = word1"<<endl;
*//or*
**if(strcmp(word,word1)!=0)** *//if you want to validate if they're different*
cout<<"word != word1"<<endl;
return 0;``
}