Iterate through each character in an array of strings

[smh95826]

I have an array of strings (ex: string dna[50]) that is holding up to fifty 10 character strings. I am trying to compare each character of each string in the array to a separate single string, also 10 characters. However, I can't seem to figure out how to iterate through each character in order to compare each letter. I feel like I am doing something wrong on line 13, but I am really not sure. C++ newbie here, and any help would be greatly appreciated! Cheers!

void displayPercent(string myDna, string dnaOfPeople[], 
     string namesOfPeople[], int numberOfPeople, int percentArray[])
{
     int i = 0;
     int j = 0;
     int counter = 0;
     int percentage = 0;
     for (i = 0; i < numberOfPeople; i++)   //loops as many times as the number of people we are comparing
     {
         for (j = 0; j < 10; j++)         //loops through all 10 characters of each string in array
         {
             if (dnaOfPeople[i][j] == myDna[j])  //compares the value of string i and character j to the chars in my string
             {
                 counter++;                         //adds to a counter each time a character is the same
             }
         }
         cout << "Percent match for " << namesOfPeople[i] << ": " << counter * 10 << "%" << endl;
     }
  }

[MikeStgt]

String-searching algorithm? -- see https://en.wikipedia.org/wiki/String-searching_algorithm

Edit: see also .. http://www.cplusplus.com/forum/general/251289/#msg1106595

[lastchance]

You need to re-set your counter:
int counter = 0;
for EACH pass of the i-loop, not just at the start.

(And please consider code tags: http://www.cplusplus.com/articles/jEywvCM9/ )

[keskiverto]

Break the problem into smaller bits.

On outer layer you have a list of words and a token word.

std::vector<std::string> words;
std::string token;
for ( auto word : words ) {
  // compare token and word
}

How to compare two words is a separate task. You could have that in a separate function.
A simpler 100% or not:

bool allornothing( const std::string& me, const std::string& you ) {
  if ( me.size() != you.size() ) return false; // size mismatch, will not compare
  return me == you;
}

Count of matches:

int match( const std::string& me, const std::string& you ) {
  if ( me.size() != you.size() ) return 0; // size mismatch, will not compare
  int count = 0;
  for ( size_t b=0; b < me.size(); ++b ) {
    if ( me[b] == you[b] ) ++count;
  }
  return count;
}

For fun, peek at: http://www.cplusplus.com/reference/numeric/inner_product/
It is somewhat similar, for in it each pair can contribute to the count, just like here.
One could replace the match() with inner_product, if one uses custom "multiplication".


Back to the list:

std::vector<std::string> words;
std::string token;
for ( auto word : words ) {
  std::cout << match( token, word ) << '\n';
}