How to convert a specific element of a String into an int Arduino/C++

Question

I was working on a converter project using Arduino/C. At a certain point in my code, a String sequence of 0's and 1's is generated, as an example: my_string = "01101"; . I want to process this data in a for loop like shown in this minimal example:

String x = "01011", y = "00011"; // These variables necessarily must have the same length

for(int i = 5; i > -1; i--) // Going from last index to first
{
    bitsum = x[i].toInt() + y[i].toInt(); // Summing up each pair of bit, here is the problem
}

My point is: is there a way to take an exact and specific element of the String and convert it to int one by one?
Thanks in advance!

Answer 1

If you are sure that the characters of my_string will always be numerals, then the typical method of obtaining a char numeral's numeric value is by just subtracting '0' . This works because the ASCII values for the numerals are arranged in order, so by subtracting '0' , you're subtracting their offset (48) from the actual 0 value.

The charAt(n) method can be used to get the character at a given index.

bitsum = x.charAt(i) - '0' + y.charAt(i) - '0';