Help with array in c++

int countFloatingPointValues( const string array[ ],int n ); Return the total number of floating-point values found in all the array elements of the passed array argument. For the purpose of this function, a floating-point value should have the form #.#, where # is one of the digits 0-9. The decimal point is optional but should only be found once for the element to count as a valid floating-point value. Return -1 if n <= 0. For example, for the array string data[ 4 ] = { "4.4.3.3", "44", "33.098", "33.098a" }; countFloatingPointValues( data, 4 ) should return the value 2 while countFloatingPointValues( data, -14 ) should return -1. According to this specification, all of the following are valid floatingPointValues: "1.0", "1", ".0101", "0.0123". What I am after is the regular expression: (0-9)+(.)?(0-9)* That means one or more digit characters followed by an optional decimal point followed by additional optional digit characters.