例3.1 温度转换

include <stdio.h>

int main ()
{
float f,c;
f=64.0;
c=(5.0/9)*(f-32);
printf (“f=%f\nc=%f\n”,f,c);
return 0;
}

3.2 利息算法

include<stdio.h>

int main ()
{
float p0=1000,ri=0.0036,r2=0.0225,r3=0.0198,p1,p2,p3;
p1=p0*(1+r1)
p2=p0*(1+r2)
p3=p0*(1+r3/2)*(1+r3/2);
printf(“p1=%f\n,p2=%f\np3=%f\n”,p1,p2,p3);
return 0;
}

例3.3 大小写字母转换

include <stdio.h>

int main()
{
char c1,c2;
c1=‘A’；
c2=c1+32;
printf ("%c\n",c2）；
printf(“%d\n",c2);
return 0;
}

例3.4 给出边长求面积

include <stdio.h>

include<math.h>

int main ()
double a,b,c,s,area;
a=3.67;
b=5.43;
c=6.21;
s=(a+b+c)/2;
area=squrt(s*(s-a)(s-b)(s-c));
printf (“a=%f\tb=%f\t%f\n”,a,b,c);
printf(“area=%f\n”,area);
return 0;
}

例3.5求ax^2+bx+c的值

include <stdio.h>

include <math.h>

int main()
{
double a,b,c,disc
,x1,x2,p,q;
scanf("%lf%lf%lf",&a,&b,&c);
disc=bb-4ac;
p=-b/(2.0a);
x1=p+q;x2=p-q;
printf (“x1=%7.2f\nx2=%7.2f\n”,x1,x2);
return 0;
}

3.6用%f输出实数，只能得到六位小数

include<stdio.h>

int main ()
{
double a=1.0;
printf ("%f\n",a/3);
return 0;
}

例3.7float型数据的有效位

include <stdio.h>

int main()
{
float a;
a=10000/3.0;
printf("%f\n",a);
return 0;
}