C++第3章课后习题习题答案.docx

第三章习题答案一、单选题1.D 2.B 3.B 4.A 5.C 6.B 7.D 8.D 9. A 10.D 11.C 12.A 13.B 14. A 15.D 16.A 17.C 18.C 19.C 20.B二、填空题1．条件、循环2．4.03．！，，||（非，与，或）4．0，1，15．(y%4==0y%100!=0)||(y%400)6．(x0y0z=0)||(x0y=0z0)||(x=0y0z0)7．ch=Ach=Z8．OK!NO!?? ERROR!9．x=yy=z10．Z11．2? 1? 112．1?? 0?? 0?13．do?while14．switch?? 循环15．2??0?16．517．1118．019．420．254三、读程序结果1. CD（ch1=’C’,ch2=’D’）2. *3. 10,9,11(a=10,b=9,c=10)4. a=2b=15. 1,0,1(a=1,b=0,c=1)6. x=5x=5x=3x=70x=0z=07. 2,0(k=2,b=0)8. 3,1 -1 3 1 -19. 8(a=8)10. 1,-2(a=1,y=-2)四、编程题1.#includeiostream#includeiomanipusing namespace std;#define PI 3.14159void main(){floatr,h;cout输入圆半径、圆柱高：endl;cinrh;coutsetiosflags(ios::fixed);coutsetprecision(2)圆周长是：2*PI*rendl;coutsetprecision(2)圆面积是：PI*r*rendl;coutsetprecision(2)圆球表面积是：4*PI*r*rendl;coutsetprecision(2)圆球体积是：4*PI*r*r*r/3endl;coutsetprecision(2)圆柱体积是：PI*r*r*hendl;}2. #includeiostreamusing namespace std;int main(){floata,p;int n;cout”请输入本金，存款年数，年利率、n”；cinanp;cout”利息为”a*p*n’\n’;return 0;}3. #includeiostream#includeiomanipusing namespace std;int main(){coutsetw(3)’*’’’’*’’‘’*’’\n’;coutsetw(2)’*’setw(6)’*’’\n’;cout’*’setw(8)’*’’\n’;cout’*’’\n’’*’’\n‘’*’’\n’’*’’\n’;cout’*’setw(8)’*’’\n’;coutsetw(2)’*’setw(6)’*’’\n’;coutsetw(3)’*’’’’*’’‘’*’’\n’;return 0;}4.#includeiostreamusing namespace std;main(){inta,b;cinab;if((a100)(b100))cout大于100的数是:a bendl;else{if(a100)cout大于100的数是:aendl;if(b100)cout大于100的数是:bendl;if((a=100)(b=100))cout两数之和是:a+bendl;}return 0;}5.#include iostreamusing namespace std;main(){int x;cinx;if((x%5==0)(x%7==0))coutYesendl;elsecoutNoendl;return 0;}6. #include iostream#include iomanipusing namespace std;int main(){charletter,letter_new;cout”请输入一个小写字母：”;cinletter;if(letter=’a’letter=’m’){letter_new=letter+1;cout”变换后的字母为”letter_new’\n’;}else if(letter=’n’letter=’z’){letter_new=letter-1;cout”变换后的字母为”letter_new’\n’;}elsecout”这不是一个小写字母”’\n’;return 0;}7. #include iostream#include iomanip#includemath.husing namespace std;int main(){floata,b,c,s;floatsin_A,cos_A;cout”请输入三角形的三条边：”；cinabc;if(!((a+b=c)(b+c=a)(a+c=b