都是自己寫的，自己測試過了，難免和學習知道上有些不同，敬請諒解，但是程序絕對原創，第三章比較簡單。
3.1
//if the rate of GDP's growth in our country is 9%,
//please write a program and output how much the GDP grows after ten year
#include <stdio.h>
#include <math.h>
int main()
{
float rate,percent,year,i;
rate=0.09;
year=10;
percent=pow(1+rate,year);//using math function
printf("The GDP has grown %f compare to 10 years ago.\n",percent);
percent=1;
for(i=0;i<10;i++)//using circulation
{
percent*=(1+rate);
}
printf("The GDP has grown %f compare to 10 years ago.\n",percent);
return 0;//dd
}3.2
//dispoit $1000 for five years has five ways,
//please compare the 5 ways.
#include <stdio.h>
#include <math.h>
int main()
{
float t0,t1,t2,t3,t4,r0,r1,r2,r3,r4;
int n=5;
t0=t1=t2=t3=t4=1000;
r0=0.0414;//1 year deposit rate
r1=0.0468;//2 year deposit rate
r2=0.054;//3 year deposit rate
r3=0.0585;//5 year deposit rate
r4=0.0072;//current deposit rate
t0*=(1+n*r3);//5 years one time
t1*=(1+2*r1);
t1*=(1+3*r2);//deposit 2 years first then 3 years
t2*=(1+3*r2);
t2*=(1+2*r1);//deposit 3 years first then 2 years
t3*=pow(1+r3,n);//one year for 5 times
t4*=pow(1+r4/4,4*n);//current deposit
printf("You will have $%.2f if you take the first method.\n",t0);
printf("You will have $%.2f if you take the second method.\n",t1);
printf("You will have $%.2f if you take the third method.\n",t2);
printf("You will have $%.2f if you take the forth method.\n",t3);
printf("You will have $%.2f if you take the fifth method.\n",t4);
return 0;//dd
}3.3
//There is a loan,calculate when it can be payed off
#include <stdio.h>
#include <math.h>
int main()
{
float m,r=0.01;
float loan=300000,pmonth=6000;
m=log10((pmonth)/(pmonth-loan*r))/log10(1+r);
printf("The money will be payed off in %.1f years.\n",m);
return 0;//dd
}3.5
//how to let a=3,b=7,x=8.5,y=71.82,c1='A',c2='a';
#include <stdio.h>
int main()
{
int a,b;
float x,y;
char c1,c2;
scanf("a=%d b=%d",&a,&b);
scanf("%f %e",&x,&y);
scanf("%c%c",&c1,&c2);
printf("a=%d b=%d\n",a,b);
printf("x=%f y=%e\n",x,y);
printf("c1=%c c2=%c\n",c1,c2);
return 0;//dd
}//translate the code China->Glmre,ASCII+4
#include <stdio.h>
int main()
{
char c1='C',c2='h',c3='i',c4='n',c5='a';//using char
int c6='C',c7='h',c8='i',c9='n',c10='a';//using int
c1+=4;
c2+=4;
c3+=4;
c4+=4;
c5+=4;
printf("China: %c%c%c%c%c\n",c1,c2,c3,c4,c5);
c6+=4;
c7+=4;
c8+=4;
c9+=4;
c10+=4;
printf("China: %c%c%c%c%c\n",c6,c7,c8,c9,c10);
return 0;//dd
}3.7
//enter r and h,output the circumference,area of the circle,the superficial area,the volume of the ball;
//the volume of column
#include <stdio.h>
int main()
{
float r,h,cc,ac,ab,vb,vc,PI=3.141;
printf("Please enter the r and h: (r,h)\n");
scanf("%f,%f",&r,&h);
cc=2*PI*r;
ac=PI*r*r;
ab=4*PI*r*r;
vb=4.0/3*PI*r*r*r;
vc=PI*r*r*h;
printf("The circum of the circle is: %.2f\n",cc);
printf("The area of the circle is: %.2f\n",ac);
printf("The superfical area of the ball is: %.2f\n",ab);
printf("The volume of the ball is: %.2f\n",vb);
printf("The volume of column is: %.2f\n",vc);
return 0;//dd
}