I have already had this problem but i forgot the reason for it's appearance

Question

for(int i = 0; i < word.length(); ++i){
std::string letter = word.at(i);
if(letter == "a")
//error

And here is another ex:

for(int i = 0; i < word.length(); ++i){
std::string letter = word.at(i);
if(word.at(i) == "a")
//also error and i know why but not
//completely to get rid of this

Answer 1

You are comparing a string to a character. You were also trying to assign a character to a string variable. Take note of the difference between double quotes and single quotes. The at() function in string class returns a character.

Answer 2

/* at() function return character at the position i. Hence, data type for letter should be char instead of std::string*/

char letter = word.at(i);

/* A character (char value) is enclosed between a single quote('a') rather than double quote ("a"). */

if(letter == 'a')

Answer 3

string::at returns a char. Use single quote 'a' for char literal, double quote is for string literal.

Answer 4

thanks guys, you are the best😁