习题2.13：设x和y为int型变量，则语句“x+=y;y=x-y;x-=y;”的功能是：#include"stdio.h"main(){intx,y;x=32768;y=32769;printf("x=%d,y=%d",x,y);}习题3-11#include"stdio.h"main(){inta=3,b=2,c=1;c-=++b;b*=a+c;{intb=5,c=12;c/=b*2;a-=c;printf("%d,%d,%d\n",a,b,c);a+=--c;}printf("%d,%d,%d",a,b,c);}习题4.5#include“stdio.h”main(){floatx,y;scanf(“%d”,&x);if(x<0.0)y=0.0;elseif((x<5.0)&&(x!=2.0))y=1.0/(x+2.0);elseif(x<10.0)y=1.0/x;elsey=10.0;printf(“%f\n”,y);习题4.6….switch(x){case1:switch(y){case0:a++;break;case1:b++;break;}case2:a++;b++;break;}…..习题4.7main(){inta=-1,b=4,k;k=(a++<=0)&&(!(b--<=0));printf(“%d%d%d\n”,k,a,b);}习题4.23main(){inta,b,c;a=10,b=20,c=30;a=25&&b--<=2&&c++?printf("***a=%d,b=%d,c=%d\n",a,b,c):printf("###a=%d,b=%d,c=%d\n",a,b,c);printf("------a=%d\n",a);}习题4.25a=b=c=0;x=35;if(1)x--;elseif(b);if(c)x=3;elsex=4;习题5.2for(x=3;x<6;x++)printf((x%2)?(“**%d”):(“##%d\n”),x);习题5.3main(){floatx,y,z;scanf(“%f,%f”,&x,&y);z=x/y;while(1){if(fabs(z)>1.0){x=y;y=z;z=x/y;}elsebreak;}printf(“%f\n”,y);}习题5.4main(){inta,b;for(a=1,b=1;a<=100;a++){if(b>=20)break;if(b%3==1){b+=3;continue;}b-=5;}}习题5.7for(y=1,x=1;y<=50;y++){if(x==10)break;if(x%2==1){x+=5;continue;}x-=3;}习题5.8for(j=10;j>3;j--){if(j%3)j--;--j;--j;printf(“%d”,j);}习题5.9main(){inti,j;for(j=10;j<11;j++){for(i=9;i<j;i++)if(!(j%i))break;if(i==j-1)printf(“%d”,j);}}习题5.12main(){intv1=0,v2=0;charch;while((ch=getchar())!=‘#’)switch(ch){case‘a’:case‘h’:default:v1++;case‘0’:v2++;}printf(“%d,%d\n”,v1,v2);}习题5.13main(){inti,j,x=0;for(i=0;i<2;i++){x++;for(j=0;j<3;j++){if(j%2)continue;x++;}x++;}printf(“x=%d\n”,x);}习题5.14main(){intx=10,y=10,I;for(i=0;x>8;y=++i)printf(“%d%d”,x--,y);}习题5.15main(){intn=4;while(n--)printf(“%d”,--n);}作业：12.#include"stdio.h"main(){inti,x=1;for(i=9;i>=1;i--)x=2*(x+1);printf("x=%d\n",x);}