第一章一．1.C2.A3.B4.A5.D6.C7.B8.D9.D10.D11.D12.A13.B14.C二．1.√2.√3.√4.×5.√6.√7.√8.√9.×10.×第二章一．1.A2.A3.C4.C5.C6.A7.BD8.B9.A10.C11.D12.B13.D14.B15.C16.D17.D18.B19.B20.B21.B二．1．×2.×3.√4.√5.×6.×7.×8.×9.×10.√11.×12.√13.√14.√15.×三．1.972.变量初始化3.符号常量4.双精度5.6.56.5,67.08.189.3010.10011.012.513.b14.1315.616.n1=%d\nn2=%d\n四．1.B2.C3.A4.D5.D6,.D7.B8.B9.A10.D11.A12.B13.C14.C第三章一．1.由表达式组成的语句称为表达式语句2.C语言使用输入输出函数是为了我们编程的方便和简洁3.真1，假0.4.c语言语句：表达式语句，函数调用语句，控制语句，复合语句，空语句二．1.D2.B3.C4.A5.B6.D7.B8.C9.Ca<bx=2x=1x=6x=7c<dA=1,b=3,c=5,d=4开始三．1.0110a<c01b<d10结束输出xx=3开始2.num<=2结束输出numnum++num=00四．#include<stdio.h>main(){ints;floatn,t,pi;t=1;pi=0;n=1;s=1;While(t>=1e-6||t<=-1e-6){pi=pi+t;n=n+2;s=-s;t=s/n;}pi=pi*4;printf("pi=%10.6f\n",pi);}#include<stdio.h>main(){inta,b,c,b;scanf("%d%d%d",&a,&b,&c);if(a>b)if(a>c)max=a;elsemax=c;elseif(b>c)max=b;elsemax=c;printf("max=%d",max);}五．1.-12.$$$3.89104.x>35.t=36.67.Dxunknow六．1.#include<stdio.h>main(){inta;printf("输入一个整数:");scanf("%d",&a);if(a%2==0)printf("偶数");elseprintf("奇数");｝2.#include<stdio.h>voidmain(){floatx,y;printf("输入一个数:");scanf("%f",&x);if(x<-1)y=x;elseif(x>1)y=2*x+1;elsey=2*x-1;printf("\n%f\n",y);}3.#include<stdio.h>voidmain(){inteng,spa,num,oth;charc;eng=spa=num=oth=0;printf("输入一串字符:");c=getchar();while(c!='\n'){if(c>='a'&&c<='z'||c>='A'&&c<='Z')eng++;elseif(c=='')spa++;elseif(c>='0'&&c<='9')num++;elseoth++;c=getchar();}printf("eng=%d,spa=%d,num=%d,oth=%d\n",eng,spa,num,oth);}4.#include<stdio.h>voidmain(){ints=0,i,k,a;for(i=1;i<=2;i++){a=1;for(k=1;k<=i;k++)a=a*k;s=s+a;}printf("sum=%d\n",s);}5.(1)#include<stdio.h>voidmain(){inta,i,k;for(i=1;i<=4;i++){for(k=1;k<=i;k++)printf("");for(a=1;a<=7;a++)printf("*");printf("\n");}}(2)#include<stdio.h>voidmain(){inta,i,k;for(i=1;i<=4;i++){for(k=1;k<=i;k++)