Question

How to get the number of digits before the decimal point in C++

Answer 1

#include <iostream>
#include <iomanip>
#include <cmath>

/**
 * Calculates the number of digits before the decimal point in a positive double.
 * For example, 89.560873 → 2 digits before the decimal.
*/
int countIntegerDigits(double value) {
    if (value == 0.0) return 1;
    
    return static_cast<int>(std::log10(std::abs(value))) + 1;
}

int main() 
{ 
    double n = 89.560873;

    // Get number of digits before the decimal point
    int digitsBeforeDecimal = countIntegerDigits(n);

    std::cout << digitsBeforeDecimal<< std::endl;
}



/*
run:
 
2
 
*/

 

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