#include"stdio.h"

#include"math.h"

int main(void)

{

double a,b,z;

printf("Enter a: b:\n");

scanf("%lf%lf",&a,&b);

if(a<=3&&b<5){

z=10;}

else if(a<=3&&b>=5){

z=10+2*b/5;}

else if(a>3&&a<=13&&b<5){

z=10+2*(a-3);}

else if(a>3&&a<=13&&b>=5){

z=10+2*(a-3)+(2*b/5);}

else if(a>13&&b<5){

z=30+3*(a-13);}

else if(a>13&&b>=5){

z=30+3*(a-13)+2*b/5;}

printf("z=%lf",z);

return 0;

}

#include"stdio.h"

#include"math.h"

int main(void)

{

double a,b,c,x1,y1,x2,y2,x3,y3,C,S,N;

printf("Enter x1,y1:\n x2,y2:\n x3,y3:\n");

scanf("%lf%lf%lf%lf%lf%lf",&x1,&y1,&x2,&y2,&x3,&y3);

a=sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));

b=sqrt((x3-x2)*(x3-x2)+(y3-y2)*(y3-y2));

c=sqrt((x3-x1)*(x3-x1)+(y3-y1)*(y3-y1));

if(a+b<c||a+c<b||b+c<a)

printf("Impossible");

else

C=a+b+c;

N=C/2;

S=sqrt(N*(N-a)*(N-b)*(N-c));

printf("C=%.2lf\n,S=%.2lf\n",C,S);

return 0;

}

心得：一开始不会做，后来在室友的帮助下做完了，但我知道不能每次都靠室友，自己应该找问题的根源，多看书，多上机