20131001国庆作业例2-4,2-5,2-6

2-4

结果1

结果2

结果3

#include<stdio.h>
int main(void)
{
    double x,y;

    printf("Enterx(x>=0):
");
    scanf("%lf",&x);
    if(x<=15){
        y=4*x/3;
    }
    else{
        y=2.5*x-10.5;
    }
    printf("y=f(%f)=%.2f
",x,y);

  return 0；
}

2-5

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

int main(void)
{
    int money,year;
    double rate,sum;

    printf("Enter money:");
    scanf("%d",&money);
    printf("Enter year:");
    scanf("%d",&year);
    printf("Enter rate:");
    scanf("%lf",&rate);
    sum=money*pow(1+rate,year);
    printf("sum=%.2f
",sum);

    return 0;
}

2-6

#include<stdio.h>
int main(void)
{
    int fahr,lower,upper;
    double celsius;

    printf("Enter lower:");
    scanf("%d",&lower);
    printf("Enter upper:");
    scanf("%d",&upper);
    printf("fahr celsius
");

    for(fahr=lower;fahr<=upper;fahr++){
        celsius=(5.0/9.0)*(fahr-32);
        printf("%d%6.1f
",fahr,celsius);
    }

    return 0;
}