c ++附加到字符串

Question

Is there an easy way to append an integer to a string?

I have a for loop like this:

for (int i = 0; i < text.length(); i++) {
  for (int g = 0; g < word.length(); g++) {
    if (text[i] == word[g]) {
      kodas.append(g);
    }
  }
}

and I need to get the index of the array which is equal, and the index of course is an integer type. But as I do this I get an error:

invalid conversion from ‘int’ to ‘const char*’ [-fpermissive]|

is there a way to fix this?

Answer 1

Use stringstream if you are working with std::strings: #include <sstream>

#include <sstream>
using namespace std;
string oldString = "old";
int toAppend = 5;
stringstream ss(toAppend);
string newString = oldString + ss.str();

newString will be "old5"

Answer 2

Yes .

You can, for example:

• use the itoa function that converts integers into strings
• make your kodas an ostringstream and "write" into it as you would to cout : kodas << g

Answer 3

The easiest is like so:

if (kodas.empty()) { kodas += ' '; }
kodas += std::to_string(g);

If you don't have C++11, use boost::lexical_cast<std::string>(g) instead.

Failing everything, you can do something terrible like this:

kodas += static_cast<std::ostringstream&>(std::ostringstream() << g).str();

Answer 4

itoa(), its the into to alpha function, should help you out. sprintf or vsprintf works too if you want to

Answer 5

There are several ways of formatting a number as a string in C++, including sprintf() , boost:lexical_cast() , and others. See The String Formatters of Manor Farm for a good comparison and additional suggestions. In addition, C++11 has std::to_string . Your compiler may or may not have it yet.