In this program, the user is asked to enter a string which is stored in the string object str.
Then, the
reverse()
function is called which is a recursive function.
Inside this function, we store the size of the input string in the
numOfChars
variable.
In the first function call,
reverse()
prints the last character of the string with the code:
cout << str[numOfChars - 1];​
Remember that strings are actually character arrays, so each individual character of a string can be represented as an index of the string array
str[]
.
In the next line, the recursive function is called:
reverse(str.substr(0, numOfChars - 1));​
Here,
substr()
gives the string upto the 2nd last character, which is passed again to the
reverse()
function.
In the next
reverse()
call, the 2nd last character is printed because the string contains one less character from the last. After this, one character from the last is cut-off from the string again and passed to the
reverse()
function.