How to append a char to a std::string?

Question

The following fails with the error prog.cpp:5:13: error: invalid conversion from ‘char’ to ‘const char*’

int main()
{
  char d = \'d\';
  std::s         


        

Answer 1

int main()
{
  char d = 'd';
  std::string y("Hello worl");

  y += d;
  y.push_back(d);
  y.append(1, d); //appending the character 1 time
  y.insert(y.end(), 1, d); //appending the character 1 time
  y.resize(y.size()+1, d); //appending the character 1 time
  y += std::string(1, d); //appending the character 1 time
}

Note that in all of these examples you could have used a character literal directly: y += 'd';.

Your second example almost would have worked, for unrelated reasons. char d[1] = { 'd'}; didn't work, but char d[2] = { 'd'}; (note the array is size two) would have been worked roughly the same as const char* d = "d";, and a string literal can be appended: y.append(d);.

Answer 2

str.append(10u,'d'); //appends character d 10 times

Notice I have written 10u and not 10 for the number of times I'd like to append the character; replace 10 with whatever number.

Answer 3

Also adding insert option, as not mentioned yet.

std::string str("Hello World");
char ch;

str.push_back(ch);  //ch is the character to be added
OR
str.append(sizeof(ch),ch);
OR
str.insert(str.length(),sizeof(ch),ch) //not mentioned above

Answer 4

the problem with:

std::string y("Hello worl");
y.push_back('d')
std::cout << y;

is that you have to have the 'd' as opposed to using a name of a char, like char d = 'd'; Or am I wrong?

Answer 5

I found a simple way... I needed to tack a char on to a string that was being built on the fly. I needed a char list; because I was giving the user a choice and using that choice in a switch() statement.

I simply added another std::string Slist; and set the new string equal to the character, "list" - a, b, c or whatever the end user chooses like this:

char list;
std::string cmd, state[], Slist;
Slist = list; //set this string to the chosen char;
cmd = Slist + state[x] + "whatever";
system(cmd.c_str());

Complexity may be cool but simplicity is cooler. IMHO

Answer 6

Use push_back():

std::string y("Hello worl");
y.push_back('d')
std::cout << y;