20131001国庆作业例2-4,2-5,2-6

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

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

return 0；
}

#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\n",sum);

return 0;
}

#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\n");

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

return 0;
}