histogram program gives strange output C++ -

i have been writing code produce horizontal histogram. program takes user input of range of numbers vector. asks user lowest value want histogram begin at, , how big want each bin be. example:

if lowestvalue = 1 , binsize = 20 , vector filled values {1, 2, 3, 20, 30, 40, 50} print like:

(bin)   (bars)  (num)(percent) [ 1-21) ####      4    57% [21-41) ##        2    28% [41-61) ##        2    28% 

here of code so:

void printhistogram(int lowestvalue, int binsize, vector<double> v) {     int binfloor = lowestvalue, binceiling = 0;     int numbins = amountofbins(binsize, (int)range(v));     (int = 0; i<=numbins; i++)     {         binceiling = binfloor+binsize;         int amoinbin = amountinbin(v,binfloor, binsize);         double perinbin = percentinbin(v, amoinbin);         if (binfloor < 10)         {             cout << "[ " << binfloor << '-' << binceiling << ") " << setw(20) << left << formatbars(perinbin) << ' ' << amoinbin << ' '<< setprecision(4) << perinbin << '%' << endl;             binfloor += binsize;         }          else         {             cout << '[' << binfloor << '-' << binceiling << ") " << setw(20) << left << formatbars(perinbin) << ' ' << amoinbin << ' '<< setprecision(4) << perinbin << '%' << endl;             binfloor += binsize;         }     } } 

and function counts how many terms in each bin:

int amountinbin(vector<double> v, int lowestbinvalue, int binsize) {      int count = 0;      (size_t i; i<v.size(); i++)      {          if (v[i] >= lowestbinvalue && v[i] < (lowestbinvalue+binsize))              count += 1;      }      return count; } 

now issue:

for reason, not counting values between 20-40. @ least far can see testing. here image of run:

any appreciated.

the code in loop doesn't initialize i, results @ best unpredictable.