第五章if語(yǔ)句練習(xí)題_百度文庫(kù)

1、第五章if語(yǔ)句練習(xí)題1.以下不正確的if語(yǔ)句形式是_Aif(x>y&&x!=y;Bif(x= =yx+=y;Cif(x!=yscanf(“%d”,&x,else scanf(“%d,&y;Dif(x 2.以下運(yùn)算符中優(yōu)先級(jí)最低的是(1,優(yōu)先級(jí)最高的是(2A ?: B&& C+ D! =3.已知int x=10,y=20,z=30;以下語(yǔ)句執(zhí)行后x,y,z的值是_if(x>yz=x;x=y;y=z;Ax=10,y=20,z=30 Bx=20,y=30,z=30Cx=20,y=30,z=10 Dx=20,y=30,z=204.以下if語(yǔ)句

2、語(yǔ)法正確的是_Aif(x>0printf(“%f”,xelse printf(“%f”,-x;Bif(x>0x=x+y;printf(“%f,x;else printf(“%f”,-x;Cif(x>0x=x+y;printf(“%f”,x;else printf(“%f”,-x;Dif(x>0x=x+y;printf(“%f,x；else printf(“%f”,-x;5.請(qǐng)閱讀以下程序:main( int a=5,b=0,c=0;if(a=b+cprintf(“* * *n”;else printf(“$ $ $n”;以上程序_A有語(yǔ)法錯(cuò)不能通過(guò)編譯 B可以通過(guò)編譯但

3、不能通過(guò)連接C輸出* * * D輸出$ $ $ 6.以下程序的運(yùn)行結(jié)果是_main( int m=5;if(m+>5printf(“%dn”,m;else printf(“%dn”,m-;A 4 B 5 C 6 D 77.當(dāng)a=1,b=3,c=5,d=4時(shí),執(zhí)行完下面一段程序后x的值是_if(a if(c x=1; elseif(a if(b else x=3;else x=6;else x=7;A 1 b 2 c 3 d 68. 有一個(gè)函數(shù)關(guān)系見下表:xy=x<0x-1x=0xx>0x+1下面程序段中能正確表示上面關(guān)系的是( A y=x+1;if(x>=0if(x=0

4、y=x;else y=x-1;b y=x-1;if(x!=0if(x>0y=x+1;else y=x;c if(x<=0if(x<0y=x-1;else y=x;else y=x+1;dy=x;if(x<=0if(x<0y=x-1;else y=x+1;9.以下程序的輸出結(jié)果是_main( int a=100,x=10,y=20,okl=5,ok2=0;if(x if(!ok1a=1;elseif(ok2 a=10;a=-1;printf(“%dn”,a;A 1 B 0 C -1 D 值不確定10.以下程序輸出結(jié)果是_main( int x=2,y=-1,z=2;

5、if(x if(y<0 z=0;else z+=1;printf(“%dn”,z;A.3 B.2 C.1 D.011.為避免在嵌套的條件語(yǔ)句if-else中產(chǎn)生二義性,C語(yǔ)言規(guī)定:else子句總是與_配對(duì).A.縮排位置相同的if B.其之前最近的ifC.其之后最近的if D.同一行上的if12.以下不正確的語(yǔ)句為_A.if(x>y;B.if(x=y&&(x! =0 x+=y;C,if(x! =yscanf(“%d”,&x;else scanf(“%d”,&y;D.if(x 12.閱讀以下程序#include main( float a, b;scan

6、f(“%f”,&a;if(a<0.0b=0.0;else if(a<0.5&&(a!=2.0b=1.0/(a+2.0;else if(a<10.0b=1.0/a;else b=10.0;printf(“%fn”,b;若運(yùn)行時(shí)輸入2.0<回車>,則上面程序的輸出結(jié)果是_A0.000000 B0.500000 C1.000000 D0.25000013.若運(yùn)行時(shí)輸入:16<回車>,則以下程序的運(yùn)行結(jié)果是( #include main( int year;printf(“Input you year:”;scanf(“%d”,&

7、;year;if(year>=18printf(“you$4.5yuan/xiaoshi”;else printf(“your$3.0yuan/xiaoshi”;14.若運(yùn)行時(shí)輸入:2<回車>,則以下程序的運(yùn)行結(jié)果是( #include main( char class;printf(“enter 1for 1stclass post or 2 for 2nd post”;scanf(“%c”,&class;if(class= =1 printf(“1st class postage is 19p”;else printf(“2nd class postage is

8、14p”;15.若運(yùn)行時(shí)輸入:4.4<回車>,則以下程序的運(yùn)行結(jié)果是(#include main( float costprice,sellingprice;printf(“enter cost price $:”;scanf(“%f”,&costprice;if(costprice>=5sellingprice=costprice+costprice*0.25;printf(“selling price(0.25$%6.2f”,sellingprice;elsesellingprice=costprice+costprice*0.30;printf(“selling

9、 price(0.30$%6.2f”,sellingprice;16.以下程序的運(yùn)行結(jié)果是( main( if(2*2= =5<2*2= =4 printf(“T”;else printf(“F”;17.請(qǐng)閱讀以下程序:main( int t,h,m;scanf(“%d”,&t;h=(t/100%12;if(h= =0h=12;printf(“%d:”,h;m=t%100;if(m<10printf(“0”;printf(“%d”,m;if(t<1200|t= =2400printf(“AM”;else printf(“PM”;若運(yùn)行時(shí)輸入:1605<回車>

10、;時(shí),程序的運(yùn)行結(jié)果是( 18.以下程序?qū)崿F(xiàn):輸入圓的半徑r和運(yùn)行標(biāo)志m,按照運(yùn)行標(biāo)志進(jìn)行指定計(jì)算.請(qǐng)?jiān)? 內(nèi)填入正確的內(nèi)容.標(biāo)志 運(yùn)算a 面積c 周長(zhǎng)b 二者均計(jì)算#define pi 3.14159main( char m;float r,c,a;printf(“input mark a c or b&&rn”;scanf(“%c%f”,&m,&r;if( 1 a=pi*r*r;printf(“area is %f”,a;if( 2 c=2*pi*r;printf(“circle is %f”,c;if( 3 a=pi*r*r;c=2*pi*r;printf

11、(“area&&circle are%f%f”,a,c;19.若運(yùn)行時(shí)輸入:5999<回車>,則以下程序的運(yùn)行結(jié)果(保留小數(shù)后一位是( main( int x;float y;scanf(“%d”,&x;if(x>=0&&x<=2999y=18+0.12*x;if(x>=3000&&x<=5999y=36+0.6*x;if(x>=6000&&x<=10000y=54+0.3*x;printf(“%6.1f”,y;20.以下程序?qū)崿F(xiàn)輸出x,y,z三個(gè)數(shù)中的最大者.請(qǐng)?jiān)? 添入正

12、確內(nèi)容.main( int x=4,y=6,z=7;int ( 1 if( 2 u=x;else u=y;if( 3 v=u;else v=z;printf(“v=%d”,v;21.以下程序?qū)崿F(xiàn):輸入三個(gè)整數(shù),按從大到小的順序進(jìn)行輸出.請(qǐng)?jiān)? 內(nèi)填入正確內(nèi)容main( int x,y,z,c;scanf(“%d%d%d”,&x,&y,&z;if( 1 c=y;y=z;z=c;if( 2 c=x;x=z;z=c;if( 3 c=x;x=y;y=c;printf(“%d,%d,%d”,x,y,z;22.以下程序?qū)斎氲膬蓚€(gè)整數(shù),按從大到小順序輸出.請(qǐng)?jiān)? 內(nèi)填正確內(nèi)容.ma

13、in ( int x,y,z;scanf(“%d,%d,”,&x,&y;if( 1 z=x;(2printf(“%d,%d”,x,y;23.以下程序?qū)斎氲囊粋€(gè)小寫字母,將字母循環(huán)后移5個(gè)位置后輸出.如a變成f,w變成b.請(qǐng)?jiān)? 填入正確內(nèi)容#include “stdio.h”main( char c;c=getchar( ;if(c>=a&&c<=u( 1 else if(c>=v&&c<=z( 2 putchar(c;24.輸入一個(gè)字符,如果它是一個(gè)大寫字母,則把它變成小寫,如果是小寫,則變成大寫,其他字符不變,請(qǐng)?jiān)?

14、 填正確內(nèi)容main ( char ch;scanf(“%c”,&ch;if( 1 ch=ch+32;else if(ch>=a&&ch<=z(2printf(“%c”,ch;25.以下程序的運(yùn)行結(jié)果是( main( int a,b,c;int s,w,t;s=w=t=0;a=-1,b=3,c=3;if(c>0s=a+b;if(a<=0if(b>0if(c<=0w=a-b;else if(c>0w=a-b;else t=c;printf(“%d%d%d”,s,w,t;26.以下程序的運(yùn)行結(jié)果是( main( int a,b,c,

15、d,x;a=c=0;b=1;d=20;if(ad=d-10;else if(! bif(! cx=15;else x=25;printf(“%dn”,d;27.以下程序的運(yùn)行結(jié)果是( #include main( int x,y=1,z;if(y!=0x=5;printf(“t%dn”,x;if(y= =0x=4;else x=5;printf(“t%dn”,x;x=1;if(y<0if(y>0x=4;else x=5;printf(“t%dn”,x;28.以下程序的運(yùn)行結(jié)果是( #include main( int x,y=-2,z=0;if(z=y<0x=4;else i

16、f(y= =0x=5;else x=6;printf(“t%dt%dn”,x,z;if(z=(y= =0x=5;x=4;printf(“t%dt%dn”,x,z;if(x=z=yx=4;printf(“t%dt%dn”,x,z;29.閱讀下面程序:main ( int s,t,a,b;scanf(“%d,%d”,&a,&b;s=1;t=1;if(a>0s=s+1;if(a>bt=s+t;else if(a= =bt=5;else t=2*s;printf(“s=%d,t=%d”,s,t;為使輸出結(jié)果t=4,輸入量a和b應(yīng)滿足的條件是( 30.請(qǐng)閱讀下面程序:main

17、( int s ,t,a,b;scanf(“%d,%d”,&a,&b;s=1;t=1;if(a>0s=s+1;if(a>bt=s+t;else if(a= =bt=5;else t=2*s;printf(“s=%d,t=%d”,s,t;為使輸出結(jié)果s=1,t=5,輸入量a和b應(yīng)滿足條件是( 31.下面程序根據(jù)以下函數(shù)關(guān)系,對(duì)輸入的每個(gè)x值,計(jì)算出y值,在( 填正確內(nèi)容xY2 x(x+2-1 2xx<=-1x-1main( int x,y;scanf(“%d,&x;if(1y=x*(x+2;else if(2y=2*x;else if(x<=-1y

18、=x-1;else( 3 ;if(y!=-1printf(“%d”,y;else printf(“error”;32.下面程序根據(jù)以下函數(shù)關(guān)系,對(duì)輸入的每個(gè)x值,計(jì)算出相應(yīng)的y值.在( 填正確內(nèi)容xyx=a或x=-a0-a sqrt(a*a-x*xx<-a或x>ax#include “math.h”main( int x,a;float y;scanf(“%d%d”,&x,&a;if( 1 y=0;else if( 2 y=sqrt(a*a-x*x;else y=x;printf(“%f”,y;33.以下程序的功能是計(jì)算一元二次方程ax2+bx+c=0的根,在( 填

19、正確內(nèi)容#include “math.h”main( float a,b,c,t,disc,twoa,term1,term2;printf(“enter a,b,c:”;scanf(“%f%f%f”,&a,&b,&c;if( 1 if( 2 printf(“no answer due to input errorn”;else printf(“the single root is%fn”,-c/b;elsedisc=b*b-4*a*c;twoa=2*a;terml=-b/twoa;t=abs(disc;term2=sqrt(t/twoa;if(3printf(“comp

20、lex rootn real part=%fimag part=%fn”, terml,term2;else printf(“real rootsn rootl=%froot2=%fn”,terml+term2,term1-term2;34.以下程序根據(jù)輸入的三角形的三邊判斷是否能組成三角形,若可以則輸出它的面積和三角形的類型.在( 填正確內(nèi)容.#include“math.h”main( float a,b,c;float s,area;scanf(“%f %f %f”,&a,&b,&c;if( 1 s=(a+b+c/2;area=sqrt(s*(s-a*(s-b*(s

21、-c;printf(“%f”,area;if( 2 printf(“等邊三角形”;else if( 3 printf(“等腰三角形”;else if(a*a+b*b= =c*c| |(a*a+c*c= =b*b| |(b*b+c*c= =a*a printf(“直角三角形”;else printf(“一般三角形”;else printf(“不能組成三角形”;35. 某郵局對(duì)郵寄包裹有如下規(guī)定:若包裹的長(zhǎng)寬高任一尺寸超過(guò)1米或重量超過(guò)30千克,不予郵寄;對(duì)可以郵寄的包裹每件收手續(xù)費(fèi)0.2元,再加上根據(jù)下表按重量wei計(jì)算的資料: 重量(千克 收費(fèi)標(biāo)準(zhǔn)(元/公斤wei<=10 0.8010 20 請(qǐng)?jiān)诔绦虻?內(nèi)填入正確的內(nèi)容.main( float len,wei,hei,wid,mon,r;scanf(“%f %f %f %f”,&len,&wid,&hei,&wei;if(len>1| |wid>1| |hei>1| |wei>30 1 ;else if(wei<10 r=0.8;else if(wei<=20