how to correctly converting char array to string in c++

Question

I have these two set of char arrays:

 char t1[]={'1','2','\0','\0'}; char t2[]={'1','2','3','4'};

I want to write a function to convert them to string, but the string size for t1 should be 2 and for t2 should be 4.

 string convert(char * data) { return string(data); }

Does a good job for t1, but crashes on t2 (t2 is not null terminated).

 string convert(char * data) { return string(data,data+4); }

Does a good job for t2, but the size of generate string for t1 is 4 and not 2.

What is the best way to write a simple and fast function to do this correctly?

Benjamin Lindley · Accepted Answer · 2014-10-15 10:56:36Z

You can take an array by reference. If you're only interested in arrays of size 4:

std::string convert(char const(&data)[4]) { return std::string(data, std::find(data, data + 4, '\0')); }

If you want something more general, you can make it a template:

template<size_t N> std::string convert(char const(&data)[N]) { return std::string(data, std::find(data, data + N, '\0')); }

Ivailo Tanusheff · Accepted Answer · 2014-10-15 12:51:25Z

If you know what is the length of the character array I may suggest you the following:

#include <string> #include <iostream> std::string sconvert(const char *pCh, int arraySize){ std::string str; if (pCh[arraySize-1] == '\0') str.append(pCh); else for(int i=0; i<arraySize; i++) str.append(1,pCh[i]); return str; } int main(){ char t1[]={'1','2','\0','\0'}; char t2[]={'1','2','3','4'}; std::string str = sconvert(t1, 4); std::cout << str << " : " << str.size() << std::endl; str = sconvert(t2, 4); std::cout << str << " : " << str.size() << std::endl; }

In the else clause you should reserve the string or use assign function.

Collectives™ on Stack Overflow

how to correctly converting char array to string in c++

2 Answers 2

Comments

2 Comments

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Related