#include<stdio.h>
int main()
{  int l,w,h;
printf("请输入箱子的长,宽,高:\n");
scanf("%d%d%d",&l,&w,&h);
if(l=w=h)
printf("该箱子是正方形。\n");
else
printf("该箱子是长方形。\n");
return 0;
}

#include<stdio.h>
int main()
{int x,y,z,d,m;float n,s;printf("请输入打印纸，墨盒，光盘的数量：\n");scanf("%d,%d,%d",&x,&y,&z);n=18*x+132*y+4.5*z; if(n>=500) d=10; else { m=n/100; switch(m) { case 1:d=5; break; case 2:d=6; break; case 3:d=7; break; case 4:d=8; break; } } s=n*(100-d)/100; printf("应付款数：%.2f\n",s); }

#include<stdio.h>
int main()
{ int year,month,days;printf("please enter year and month :\n");scanf("%d%d",&year,&month);switch(month){case 2:if (year%4==0&&year%100!=0||year%400==0) days=29; else days=28;break; case 1: case 3: case 5: case 7: case 8: case 10: case 12:days=31;break; case 4: case 6: case 9: case 11:days=30;break; } printf("%d年%d月有%d天\n",year,month,days); return 0; }

#include <stdio.h>
int main()
{
int x,n,y;
float sum;
printf("请选择：1.日用品 2.文具 3.食品\n");
scanf("%d",&x);
switch(x) { case 1:printf("请选择：1.牙刷（3.5\支） 2.牙膏（6.2元\支）\n"); printf(" 3.肥皂（2元\支） 4.毛巾（8.6元\条）\n"); scanf("%d",&y); printf("数量？"); scanf("%d",&n); switch(y) { case 1:sum=3.5*n;break; case 2:sum=6.2*n;break; case 3:sum=2*n;break; case 4:sum=8.6*n;break; } break; case 2:printf("请选择：1.笔（3\支） 2.笔记本（1.2元\个）\n"); printf(" 3.文件夹（12元\个） 4.文具盒（8.6元\个）\n"); scanf("%d",&y); printf("数量？"); scanf("%d",&n); switch(y) { case 1:sum=3*n;break; case 2:sum=1.2*n;break; case 3:sum=12*n;break; case 4:sum=8.6*n;break; } break; case 3:printf("请选择：1.白糖（3.6\包） 2.盐（1元\包）\n"); printf(" 3.饼（2元\个） 4.方便面（3.6元\包）\n"); scanf("%d",&y); printf("数量？"); scanf("%d",&n); switch(y) { case 1:sum=3.6*n;break; case 2:sum=1*n;break; case 3:sum=2*n;break; case 4:sum=3.6*n;break; } break; } printf("总计:%.2f元\n",sum); }

#include<stdio.h>
#include<math.h>
int main()
{
double x=1000/3.0;
double y=x-333.0;
double z=3*y-1.0;
printf("x=%lf\n",x); printf("y=%lf\n",y); printf("z%lf\n",z); if(z==0) printf("z==0.\n"); else printf("z不等于0.\n"); }

#include<stdio.h>
int main()
{int num=20;if(5<num&&num<10)printf("%d in range (5,10)!\n",num);elseprintf("%d out of range (5,10)!\n",num); }