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

user_129376 0
Viewed 391510

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

int main()
{
  char d = 'd';
  std::string y("Hello worl");
  y.append(d); // Line 5 - this fails
  std::cout << y;
  return 0;
}

I also tried, the following, which compiles but behaves randomly at runtime:

int main()
{
  char d[1] = { 'd' };
  std::string y("Hello worl");
  y.append(d);
  std::cout << y;
  return 0;
}

Sorry for this dumb question, but I've searched around google, what I could see are just "char array to char ptr", "char ptr to char array", etc.

c++ string
14 Answers

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
user_27390180

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

user_46074190

there are three ways to do this:
for example, we have code like this:
std::string str_value = "origin";
char c_append = 'c';

  1. we usually use push_back().
    str_value.push_back(c)
  2. use += .
    str_value += c
  3. use append method.
    str_value.append(1,c)
    And you can learn more about the methods of string from http://www.cplusplus.com/reference/string/string/
user_29948130
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