阅读程序写结果试题第四章选择结构（共20道题）1.（于蕾）#include<stdio.h>voidmain(){intx,y,t;x=7;y=9;if(x<y){t=x;x=y;y=t;}printf("%d,%d\n",x,y);}运行结果：9,72.（于蕾）#include<stdio.h>voidmain(){intx=1,a=2,b=3;switch(x){case1:a--;break;case2:b++;break;case3:a++;b++;}printf("\na=%d,b=%d\n",a,b);}运行结果：a=1,b=33.（于蕾）#include<stdio.h>voidmain(){charch1='E';if(ch1>='A')ch1++;elsech1+=32;printf("ch1=%c\n",ch1);}运行结果：ch1=F4.（于蕾）#include<stdio.h>voidmain(){intx,y,t;x=5;y=3;if(x>y){t=x;x=y;y=t;}printf("%d,%d\n",x,y);}运行结果：3,55.（王伟）#include<stdio.h>intmain(){inta,b,c,m;printf("Enterthreeintegers:");scanf("%d%d%d",&a,&b,&c);if(a<=b)m=a;elsem=b;if(c<m)m=c;printf("m=%d\n",m);return0;}输入：212223<回车>运行结果：m=216.（王伟）#include<stdio.h>intmain(){charch1='a',ch2='B',ch3='E';if(ch1>ch2)if(ch2>ch3)ch3++;else--ch3;printf("ch3=%c\n",ch3);return0;}运行结果：ch3=D7.（王伟）#include<stdio.h>intmain(){floatx,y;scanf("%f",&x);switch((int)x/10){case0:y=1.0;printf("y=%f\n",y);break;case1:y=2*x+1;printf("y=%f\n",y);break;case2:y=3*x*x+2;printf("y=%f\n",y);break;default:printf("Nodefinition.\n");}return0;}输入：15.3<回车>运行结果：y=31.6000008.（王伟）#include<stdio.h>intmain(){charch1='A',ch2='B';switch(ch1){case'A':switch(ch2){case'B':printf("Good!\n");break;case'A':printf("Better!\n");break;}case'B':printf("Best!\n");break;}return0;}运行结果：Good!Best!9．（王锋）#include<stdio.h>voidmain(){floatscore;score=100;if(score<60)printf("E\n");elseswitch((int)score/10){case10:case9:printf("A\n");case8:printf("B\n");case7:printf("C\n");break;case6:printf("D\n");break;default:printf("Error\n");}}运行结果：ABC10．（王锋）#include<stdio.h>voidmain(){inti=0，a=2；if(i==0)printf(“**”)；elseprintf(“$$”)；printf(“*”)；}运行结果：***11.（王锋）#include<stdio.h>voidmain(){intm=10,n=0,p=4,q=20;if(m)if(n)q=15-m;elseq=25+m;elseif(