how tot know the number of digits in a number in cpp code example

Example 1: how to find how many digits a number has in c++

#include <iostream>
#include <cmath>

unsigned int getNumberOfDigits (int i)
{
    return i > 0 ? log10((double) i) + 1 : 1;
}

int main()
{
	std::cout << "Number of digits: " << getNumberOfDigits(/*Example*/6738) << std::endl;  
	return 0;
}

Example 2: c++ get digits of integer

int iNums = 12345;
int iNumsSize = 5;
for (int i=iNumsSize-1; i>=0; i--) {
    int y = pow(10, i);
    int z = iNums/y;
    int x2 = iNums / (y * 10);
    printf("%d-",z - x2*10 );
}