C++ : display a bar chart of array data using * -

i making program in c++11 represents yearly rainfall statistics. have completed program stuck in last stage. need design/display bar chart using *, display data array. example: uk monthly rainfall amount (mm) in 2015 are: 154.3, 79.2, 95.6, 46.3, 109.6, 55.1, 109.5, 107.4, 54.0, 72.2, 176.0, 230.0 each month consecutively.

i want bar chart this:

0 - 50 : * 50 - 80 : **** 80 - 110 : **** 110 - 140 :  140 - more : *** 

this code wrote gives me incorrect output

void rainfall::outputbarchart() const { cout<< "bar chart rainfall amount:"<< endl;  const size_t frequencysize= 5; array<unsigned int, frequencysize > frequency = { };   for(int mark : amount) ++frequency[mark / 50];  for(size_t count = 0; count < frequencysize; ++count) {  if (count == 0) cout << " 0-49: "; else cout<< count * 50 << "-"<< (count * 50) + 30 << ": ";         (unsigned int stars = 0; stars < frequency[count]; ++stars)        cout<< '*';        cout << endl; } } 

it gives me following bar chart in output

0 - 49 : * 50 - 80 : ***** 100 - 130 : *** 150 - 180 : ** 200 - 230 : ** 

try matrix hold "chart". this:

char chart[][] = char[12][4];  // fill "chart" blanks!  (auto idx=0; idx<12; ++idx) {     if (rain[idx] <= 50)     {         chart[idx][3] = '*';     } else if (rain[idx] > 50 && rain[idx] <= 80)     {         chart[idx][3] = '*';         chart[idx][2] = '*';         chart[idx][1] = '*';         chart[idx][0] = '*';      } //etc cover cases }  // print matrix (auto idxcol=0; idxcol<4; ++idxcol) {     (auto idxln=0; idxln<12; ++idxln)         std::cout << chart[idxln][idxcol];     std::cout << std::endl; } 

it can optimized i'm sure can that.