白皮 Chapter 1

#include<stdio.h>
#include<math.h>

int main()
{
    int a,b,c;
    double ave;
    scanf("%d%d%d",&a,&b,&c);
    ave=(a+b+c)/3;
    printf("%.3lf",ave);
    return 0;
}

#include<stdio.h>
#include<math.h>

int main()
{
    double f,c;
    scanf("%lf",&f);
    c=5*(f-32)/9;
    printf("%.3lf",c);
    return 0;
}

#include<stdio.h>
#include<math.h>

int main()
{
    int n,s;
    scanf("%d",&n);
    s=(1+n)*n/2;
    printf("%d",s);
    return 0;
}

#include<stdio.h>
#include<math.h>

int main()
{
    int n;
    double m;
    const double pi=4.0*atan(1.0);
    scanf("%d",&n);
    m=(float) n/180*pi;
    printf("%.3lf %.3lf",sin(m),cos(m));
    return 0;
}

#include<stdio.h>
#include<math.h>

int main()
{
    double x1,y1,x2,y2,d;
    scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);
    d=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
    printf("%.3lf",d);
    return 0;
}