Question

[ Write in C not C++]

Define a C function int round10(double n) that returns the closest integer of n which is
divisible by 10. For example, if n = 16.0, the return value is 20 and if n = 32.34, the return
value is 30.

Answer 1

#include <stdio.h>

int round10(double n){
    int k = n;
    int n1 = ((k+10)/10)*10;
    int n2 = (k/10)*10;
    if((n1-n)<(n-n2)){
        return n1;
    }
    else{
        return n2;
    }
}

int main()
{
    printf("%d\n",round10(16.0));
    printf("%d\n",round10(32.34));
    return 0;
}

int round10(double n){
    int k = n;
    int n1 = ((k+10)/10)*10;
    int n2 = (k/10)*10;
    if((n1-n)<(n-n2)){
        return n1;
    }
    else{
        return n2;
    }
}