Question

How to round a float to N decimals in C++

Answer 1

#include <iostream>
#include <iomanip>

int main() {
    float number = 82.79521;
 
    std::cout << std::fixed << std::setprecision(2) << number;
}




/*
run:

82.80

*/

 

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Answer 2

#include <iostream>
#include <iomanip>

int main() {
    float number = 82.73521;
 
    std::cout << std::fixed << std::setprecision(2) << number;
}




/*
run:

82.74

*/

 

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Answer 3

#include <iostream>
#include <iomanip>

int main() {
    float number = 82.73165;
 
    std::cout << std::fixed << std::setprecision(2) << number;
}




/*
run:

82.73

*/

 

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Answer 4

#include <iostream>
#include <cmath>

float round_float(float number, unsigned char decimals) {
    float pow_10 = pow(10.0f, (float)decimals);
    
    return round(number * pow_10) / pow_10;
}

int main() {
    float number = 82.73165;
 
    std::cout << round_float(number, 3);
}




/*
run:

82.732

*/

 

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