第6章 习题参考答案.doc 6页

'《C语言程序设计》习题参考答案第6章习题参考答案1.判断题12345678910××√√×√××××2.选择题12345DBACD3.填空题（1）char*printch(int,char);（2）intstrlen(char*);（3）intmin(int*);（4）intrandom(void);（5）intdigits(double,int);4.程序阅读题（1）(127)10=(7F)16（2）30（3）a=64,b=64（4）(3,6)5.程序填空题（1）rand()%10+"0"s,N,ca[i]-‘0’（2）5i=3;i<=2*n-1;i=i+2-t/i/(i-1)（3）chars[]sign=-1digit=0digit=digit*10+(s[k]-‘0’)（4）r=f(n)n=0z==x*x+y*y6.编程题（1）#includeintjfnum(intn);main(){inti;for(i=100;i<=999;i++)if(judge(i))printf("%dn",i);}intjudge(intn){intn1,n2,n3,flag;if(n<100||n>999)printf("error!"); 《C语言程序设计》习题参考答案else{n1=n%10;n2=(n/10)%10;n3=n/100;if(n==n1*n1*n1+n2*n2*n2+n3*n3*n3)flag=1;elseflag=0;}return(flag);}（2）floatmysqr(floata,floateps){floatx0,x1,t;if(a<0)printf("error!");else{x0=a/2.0;do{x1=(x0+a/x0)/2.0;t=fabs(x1-x0);x0=x1;}while(t>eps);}return(x1);}（3）voidcode(chars[],intn){inti;for(i=0;i"z"||s[i]>"Z"&&s[i]<"a")s[i]=s[i]-26;}}voidrecode(chars[],intn){inti;for(i=0;i"Z")s[i]=s[i]+26;}}（4）intleapyear(intyear);main(){intyear;printf("Inputyearnumber:");scanf("%d",&year);if(leapyear(year)==1)printf("n%disleapyearn",year);elseprintf("n%disnotleapyearn",year);}intleapyear(intyear){if(year%4==0&&year%100!=0||year%400==0)return(1);elsereturn(0);}（5）#includechar*search(char*s,charc){intflag;flag=0;while(*s!=""){if(*s==c){flag=1;break;}s++;}if(flag==1)return(s);elsereturn(NULL);}（6）#includevoidmaxmin(inta,intb,intc,int*max,int*min);main(){inta,b,c,max,min;printf("nPleaseinputthreeintegers:n"); 《C语言程序设计》习题参考答案scanf("%d,%d,%d",&a,&b,&c);maxmin(a,b,c,&max,&min);printf("max=%d,min=%d",max,min);}voidmaxmin(inta,intb,intc,int*max,int*min){if(a>b){*max=a;*min=b;}if(c>*max)*max=c;if(c<*min)*min=c;}（7）#include#includevoidgetdata(inta[],intn);/*随机生成数据函数的原型声明*/voidprintdata(inta[],intn);/*输出数据函数原型声明*/voidsort(inta[],intn);/*排序函数原型声明*/floataverage(inta[],intn);/*求平均值函数原型声明*/voidcount(inta[],intn,floatx,intb[]);/*统计函数原型声明*/main(){inta[20],b[3];floatx;getdata(a,20);printf("nInitialize:n");printdata(a,20);sort(a,20);printf("nSort:n");printdata(a,20);x=average(a,20);printf("nAverage:%fn",x);count(a,20,x,b);printf("n>=<:n");printdata(b,3);}voidgetdata(inta[],intn){inti;randomize();for(i=0;ia[j])k=j;t=a[i];a[i]=a[k];a[k]=t;}}floataverage(inta[],intn){floats;inti;s=0.0;for(i=0;ix)b[0]++;elseif(a[i]==x)b[1]++;elseb[2]++;}（8）#include#include#defineN20 《C语言程序设计》习题参考答案voidmidstr(chars[],intm,intn);voidmain(){chars[N];intm,n;gets(s);do{scanf("%d%d",&m,&n);}while(m>n);if(n>strlen(s))n=strlen(s);midstr(s,m,n);puts(s);}voidmidstr(chars[],intm,intn){inti,k;for(k=0,i=m-1;i<=n;i++)s[k++]=s[i];}（9）intf(intn){if(n<0)printf("error");else{if(n==0)return0;elseif(n==1)return1;elsereturnf(n-2)+f(n-1);}}'