Как узнать длину числа?

#include <stdio.h>
#include <conio.h>
int main(){
int numb = 0;
int count = 0; 
printf("input numb\t");scanf("%d",&numb);
while(numb){
numb/=10;
count++;
}
int n = count;
printf("count numbers %d",n);
printf("\n");
return 0;
}

#include <iostream>
#include <sstream>
 
int main(){
    unsigned long num;
    std::cout << "Number: ";
    std::cin >> num;
    std::ostringstream ost;
    ost << num;
    std::cout << ost.str().size() << " digits." << std::endl;
    
    return 0;
}

#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <ctime>
 
int DigitCountGeniusIgnat(int number) {
  int result = 0;
  
  while (number != 0) {
    number /= 10;
    result++;
  }
 
  return result;
}
 
int DigitCountManjak(int number) {
  char buffer[65];
  int base = 10;
 
  itoa(number, buffer, base);
 
  return strnlen(buffer, _countof(buffer))
}
 
typedef int (*func_ptr)(int);
 
double Duration(const int* arr, int size, func_ptr func) {
  const std::clock_t start = std::clock();
 
  for (int i = 0; i < size; ++i)
    int count = func(arr[i]);
 
  const std::clock_t finish = std::clock();
 
  return static_cast<double>(finish - start) / CLOCK_PER_SEC;
}
 
int main() {
  const int  size = 1000000;
        int* arr  = new int[size];
 
  std::generate(arr, arr + size, std::rand());
 
  std::cout << "DigitCountGeniusIgnat duration: " << Duration(arr, size, DigitCountGeniusIgnat) << std::endl;
  std::cout << "DigitCountManjak duration: "      << Duration(arr, size, DigitCountManjak     ) << std::endl;
  
  return 0;
}

Код: CyBOSSeR 
int DigitCountGeniusIgnat(int number) {
  int result = 0;
  
  while (number != 0) {
    number /= 10;
    result++;
  }
 
  return result;
}

int DigitCount(int number) {
  int result = 1;
  
  while ((number /= 10) != 0) 
    result++;
 
  return result;
}