Question

How to round a number down to the nearest 10 in C++

Answer 1

#include <iostream>
#include <cmath>
 
int roundDownToNearest10(double num) {
    return (int)floor(num / 10) * 10;
}
 
int main() {
    std::cout << roundDownToNearest10(33) << "\n";
    std::cout << roundDownToNearest10(59) << "\n";
    std::cout << roundDownToNearest10(599.99) << "\n";
    std::cout << roundDownToNearest10(3.14) << "\n";
    std::cout << roundDownToNearest10(2) << "\n";
    std::cout << roundDownToNearest10(19) << "\n";
    std::cout << roundDownToNearest10(-12) << "\n";
    std::cout << roundDownToNearest10(-101) << "\n";
    std::cout << roundDownToNearest10(-109) << "\n";
}
 
 
 
 
/*
run:
 
30
50
590
0
0
10
-20
-110
-110
 
*/

 

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