c++ how I do a variable to take valors until at a condition code example

Example 1: c++ declare variable

std::string str = "text";	// stores a string
int    foo = 3;				// stores any integer
float  bar = 3.14;			// stores 32 bit number
double baz = 3.14159265;	// stores 64 bit number

Example 2: c++ program how to let the user choose different game modes

int getMode(int *virus, int *frequency, int numVir)
{
   int count = 0,
	   index = 0,
	   mode = 0,
	   frLow = 0,
           total = 0;

   for (index = 0; index < numVir; index++)
   {
	  count = 1;

	  while (*(virus + index) == *(virus + index + 1))
	  {
		 ++count;
		 ++index;
	  }
	  
	  *(frequency + index) = count;
	  
	  if (*(frequency + index) > frLow)
	  {
		 frLow = *(frequency + index);
                 total += *(frequency + index);
		 mode = *(virus + index);
	  }

	  else if (frLow == 1 || frLow == *(frequency + index))
	  {
		 return -1;
	  }
   }

    return mode;
}