C语言程序设计6-9章编程

第六章5. 编程题（1）VC提供的int rand(void)产生的实际上是0～32767(short型的最大数)的伪随机数，伪随机数总是以一个相同的数为起始值(种子)，运用递推的原理来生成的。

所以，如果只使用rand函数，每次运行所形成的伪随机数列也相同，失去了随机意义。

但这样便于程序调试。

VC的rand()函数默认以1为种子。

要解决这个问题，需要在每次产生随机序列前，先指定不同的种子，这样计算出来的随机序列就不会完全相同了。

VC提供的void srand(unsigned int seed)将seed作为种子，如果以time函数值(即当前时间)作为种子数，那么就可以保证随机性了，因为两次调用rand函数的时间通常是不同的。

也可以使用srand函数来人为指定种子数。

若要产生ａ～ｂ之间的一个随机数，则可用a + rand() % (b-a+1)表示。

若要0~1的小数，则可以先取得0~10的整数，然后均除以10即可得到随机到十分位的10个随机小数；若要得到随机到百分位的随机小数，则需要先得到0~100的整数，然后均除以100，其它情况依此类推。

#include <stdio.h>#include <stdlib.h>#include <time.h>main(){int a[12],count=0,i;srand((unsigned) time(NULL));for (i=0;i<12;i++)a[i]=5+rand()%11;for(i=0;i<12;i++){printf("%5d",a[i]);count++;if(count%4==0)printf("\n") ;}}（2）#include <stdio.h>#define N 5main(){int a[N],max,min,i,sum=0,count=0;float av;for(i=0; i<N; i++)scanf("%d",&a[i]);max=min=a[0];for(i=0; i<N; i++){sum+=a[i];if(a[i]>max)max=a[i];if(a[i]<min)min=a[i];}av=(float)sum/5;for(i=0; i<N; i++)if(a[i]>av)count++;printf("max:%d\nmin:%d\nav:%f\ncount:%d",max,min,av,count);}（3）#include <stdio.h>main(){int score[30]; /*={61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,85,89,90,33,44,55,91,92,93}; //不必赋初值，这是为调试程序方便*/int i,count90=0,count80=0,count70=0,count60=0;for(i=0;i<30;i++){printf("intput NO. %d student's score:",i+1);scanf("%d",score+i);}for(i=0;i<30;i++){if(score[i]>=90){count90++;count80++;count70++;count60++;}else if(score[i]>=80){count80++;count70++;count60++;}else if(score[i]>=70){count70++;count60++;}else if(score[i]>=60)count60++;}printf("0~59:%d\n60~69:%d\n70~79:%d\n80~89:%d\n90~100:%d",30-count60,count 60-count70,count70-count80,count80-count90,count90);printf("\n60 or higher:%d\n70 or higher:%d\n80 or higher:%d\n90 or higher:%d\n",count60,count70,count80,count90);}（4）1、#include <stdio.h>main(){char a[45];int i,j,k;for(i=0;i<45;i++)a[i]=' ';for(i=0;i<5;i++){for(j=0;j<i;j++)a[9*i+j]=' ';for(k=0;k<5;k++)a[9*i+j+k]='*';}j=0;for(i=0;i<45;i++){printf("%c",a[i]);j++;if(j%9==0)printf("\n");}}2、#include <stdio.h>main(){char a[5][9];int i,j,k;for(i=0;i<5;i++)for(j=0;j<9;j++)a[i][j]=' ';for(i=0;i<5;i++){for(j=0;j<i;j++)a[i][j]=' ';for(k=0;k<5;k++)a[i][j+k]='*';}for(i=0;i<5;i++){for(j=0;j<9;j++)printf("%c",a[i][j]);printf("\n");}}(5)# include <stdio.h># define N 4main(){int i,j,a[][N]={21,12,13,24,25,16,47,38,29,11,32,54,42,21,33,10}; printf("\nThe original array:\n");for(i=0;i<N;i++){for(j=0;j<N;j++)printf("%2d ",a[i][j]);printf("\n");}for(i=1;i<N;i++){for(j=0;j<i;j++){a[i][j]=a[i][j]+a[j][i];a[j][i]=0;}}printf("\nThe result is:\n");for(i=0;i<N;i++){for(j=0;j<N;j++)printf("%2d ",a[i][j]);printf("\n");}}第七章4 、编程题(1)#include <stdio.h>long act(long n){if (n==1||n==0) return 1;else{return n*act(n-1);}}main(){int n=3;printf("n!=%ld",act(n));}（2）#include <stdio.h>void mmax(float a[],int n);main(){float a[6];int i;for(i=1; i<=5; i++)scanf("%f",&a[i]);a[0]=1;mmax(a,5);printf("%f %d\n",a[(int)a[0]],(int)a[0]); }void mmax(float a[],int n){if(n<=0)return;elseif(a[n]>a[(int)a[0]])a[0]=n;mmax(a,n-1);}（3）#include <stdio.h>#include <string.h>int start;int fun(char str[]);main(){char a[40];int i,num;gets(a);num=fun(a);if(num==-1)printf("input string error or no have 'A'\n");else{printf("%d\n",num);for(i=start; i<start+num; i++)printf("%c",a[i]);printf("\n");}}int fun(char str[]){int count=0,i=0,len,flag=0;len=strlen(str);while((!flag) && i<len){if(str[i]=='A') flag=1;i++;}if(flag==0) return -1;start=i;while(flag && i<len){if(str[i++]=='A') flag=0;else count++;}if(flag==1) return -1;return count;}(4)my_strcpy( char dst[], char src[]){int i=0;while(src[i]!='\0'){dst[i]=src[i] ;i++;}dst[i]= '\0';}int main(){char a[12]; char b[12];gets(b);my_strcpy(a,b);puts(a);}（5）#include <stdio.h>#include <string.h>void fun(char str[],int a[])//不使用数组时，可使用全局变量保存统计结果{int i=0;a[0]=a[1]=a[2]=a[3]=0;while(str[i]!='\0'){if(str[i]>='A' && str[i]<='Z' || str[i]>='a' && str[i]<='z')a[0]++;else if(str[i]>='0' && str[i]<='9')a[1]++;else if(str[i]==' ')a[2]++;elsea[3]++;i++;}}int main(){char s[80];int a[4];gets(s);fun(s,a);printf("letters:%d\tdigits:%d\tspaces:%d\tother the character:%d\n",a[0],a[1],a[2],a[3]); }第8章1．选择题：DABAD2．编程题(1)/*习题8-2-1 */#define ISALPHA(a) (((a)>='A'&&(a)<='Z')||((a)>='a'&&(a)<='z'))main(){ char c;scanf("%c",&c);printf("%d\n",ISALPHA(c));}(2)/*习题8-2-2 */#define SWAP(t,x,y) {t w; w=x; x=y; y=w; }main(){ double a=99.99,b=11.11;SWAP(double,a,b);printf("%f,%f\n",a,b);}(3)/*习题8-2-3 */#include "stdio.h"#define MAX 80#define CHANGE 1main(){ char str[MAX];int i;printf("Input text:\n");gets(str);#if(CHANGE){ for (i=0;i<MAX;i++){ if(str[i]!='\0')if(str[i]>='a'&&str[i]<'z'||str[i]>='A'&&str[i]<'Z')str[i]+=1;else if(str[i]=='z'||str[i]=='Z')str[i]-=25;}}#endifprintf("output:\n%s",str);}(4)/*习题8-2-4 */#define LEAP_YEAR(y) (y%4==0)&&(y%100!=0)||(y%400==0) main(){ int year;printf("Input year:");scanf("%d",&year);if(LEAP_YEAR(year))printf("%d is a leap year.\n",year);elseprintf("%d is not a leap year.\n",year);}(5)/*习题8-2-5.h */#ifndef __X8_2_5_H#define __X8_2_5_H#define AVER(a,b,c) (a+b+c)/3.0#endif/*习题8-2-5 */#include "X8-2-5.h"{ int a,b,c;printf("Input three integers a,b,c:");scanf("%d,%d,%d",&a,&b,&c);printf("Average is %f.\n",AVER(a,b,c));}第9章4编程题(1)/*习题9-4-1 */void move(int array[20],int n,int m) ;main(){ int number[20],n,m,i;printf("How many numbers?"); /*共有多少个数*/scanf("%d",&n);printf("Input %d numbers:\n",n); /*输入n个数*/for(i=0;i<n;i++)scanf("%d",&number[i]);printf("How many place you want to move?"); /*后移多少个位置*/scanf("%d",&m);move(number,n,m); /*调用move函数*/printf("Now,they are:\n");for(i=0;i<n;i++)printf("%d ",number[i]);}void move(int array[20],int n,int m) /*循环后移函数*/{ int *p,array_end;array_end=*(array+n-1);for(p=array+n-1;p>array;p--)*p=*(p-1);*array=array_end;m--;if(m>0) move(array,n,m); /*递归调用，当循环次数m减至0时，停止调用*/ }(2)/*习题9-4-2 */#include<stdio.h>#include<string.h>#define TOTAL 6int mseek(char*str[],char xstr[],int n)for(i=0; i<n; i++){ if(strcmp(str[i],xstr)==0)return 1;}return 0;}main(){ char*name[TOTAL]={"Lining","Linshan","Tianyuan","Zhangqiang","Haipo","Fangbing"};char xname[20];printf("enter a name:");gets(xname);if(mseek(name,xname,TOTAL))printf("Found!\n");elseprintf("Not found!\n");}(3)/*习题9-4-3 */#include <stdio.h>#include <string.h>void fun(char *str,int num[4]){ int i;for(i=0; i<4; i++) num[i]=0;while(*str!='\0'){ if(*str>='a' && *str<='z' || *str>='A' && *str<='Z')num[0]++;else if(*str==' ')num[1]++;else if(*str>='0' && *str<='9')num[2]++;elsenum[3]++;str++;}}#define N 80main(){ int string[N];int n[4],i;gets(string);fun(string,n);for(i=0; i<4; i++)printf("%d\t",n[i]);}(4)/*习题9-4-4 *//* 调试时，可这样输入数据：*//*11 12 13 14 1521 22 23 24 2531 32 33 34 3541 42 43 44 4551 52 53 54 55 */#include <stdio.h>main(){ int a[5][5],*p,i,j;void change(int *p);printf("Input matrix:\n");for(i=0;i<5;i++) /*输入矩阵*/for(j=0;j<5;j++)scanf("%d",&a[i][j]);p=&a[0][0]; /*使p指向0行0列元素*/ change(p); /*调用函数, 实现交换*/printf("Now, matrix: \n");for(i=0;i<5;i++) /*输出已交换的矩阵*/{ for(j=0;j<5;j++)printf("%4d",a[i][j]);printf("\n");}}void change(int *p) /*交换函数*/{ int i,j,temp;int *pmax,*pmin;pmax=p;pmin=p;for(i=0;i<5;i++) /*找最大值和最小值的地址,并赋给pmax,pmin*/ for(j=0;j<5;j++){ if(*pmax<*(p+5*i+j)) pmax=p+5*i+j;if(*pmin>*(p+5*i+j)) pmin=p+5*i+j;}temp=*(p+12); /*将最大值换给中心元素*/ *(p+12)=*pmax;*pmax=temp;temp=*p; /*将最小值换给左上角元素*/ *p=*pmin;*pmin=temp;pmin=p+1;for(i=0;i<5;i++) /*找第二最小值的地址赋给pmin*/ for(j=0;j<5;j++)if(((p+5*i+j)!=p)&&(*pmin>*(p+5*i+j))) pmin=p+5*i+j;temp=*pmin; /*将第二最小值换给右上角元素*/*pmin=*(p+4);*(p+4)=temp;pmin=p+1;for(i=0;i<5;i++) /*找第三最小值的地址赋给pmin*/ for(j=0;j<5;j++)if(((p+5*i+j)!=(p+4))&&((p+5*i+j)!=p)&&(*pmin>*(p+5*i+j)))pmin=p+5*i+j; /*将第三最小值换给左下角元素*/ temp=*pmin;*pmin=*(p+20);*(p+20)=temp;pmin=p+1;for(i=0;i<5;i++) /*找第四最小值的地址赋给pmin*/ for(j=0;j<5;j++)if(((p+5*i+j)!=p)&&((p+5*i+j)!=(p+4))&&((p+5*i+j)!=(p+20))&&(*pmin>*(p+5*i+j))) pmin=p+5*i+j;temp=*pmin; /*将第四最小值换给右下角元素*/*pmin=*(p+24);*(p+24)=temp;}(5)/*习题9-4-5 *//*可以专门编写一个函数求各学生的平均分，存到aver[4]数组*/#include <stdio.h>void avcour1(float score[][5]);void fali2(int num[4],float score[4][5]);void good(int num[4],float score[4][5]);main(){int i,j,num[4];//数组num代表学号float score[4][5];printf("Input NO. and scores: \n");for(i=0;i<4;i++){ printf("NO.");scanf("%d",&num[i]);printf("scores:");for(j=0;j<5;j++)scanf("%f",&score[i][j]);}printf("\n\n");avcour1(score); /*求出第一门课的平均成绩*/printf("\n\n");fali2(num,score); /*找出2门课不及格的学生*/printf("\n\n");good(num,score); /*找出成绩好的学生*/}void avcour1(float score[][5]) /*第一门课的平均成绩的函数*/{ int i;float sum,average1;sum=0.0;for(i=0;i<4;i++)sum=sum+score[0][i]; /*累计每个学生的得分*/average1=sum/4; /*计算平均成绩*/printf("course 1 average score: %6.2f. \n",average1);}void fali2(int num[4],float score[4][5])/*找两门以上课程不及格的学生的函数*/{ int i,j,k,label;float sum=0;printf("= = = = = = = =Student who is fail = = = = = = = = = = = =\n");printf(" NO.");for(i=0;i<5;i++)printf("%10d",i+1);printf(" average\n");for(i=0;i<4;i++){ label=0;for(j=0;j<5;j++)if((score[i][j])<60.0) label++;if(label>=2){ printf("%5d",num[i]);for(k=0;k<5;k++){ printf("%10.2f",score[i][k]);sum+=score[i][k];}printf("%10.2f\n",sum/5);}}}void good(int num[4],float score[4][5])/*找成绩优秀的学生(各门85分以上或平均90分以上)的函数*/{ int i,j,k,n;float sum=0,aver[4];printf("= = = = = = = =Student whose score is good= = = = = = = =\n");printf(" NO.");for(i=0;i<5;i++)printf("%10d",i+1);printf(" average\n");for(i=0;i<4;i++){ n=0;sum=0;for(j=0;j<5;j++){if((score[i][j])>85.0) n++;sum+=score[i][j];}aver[i]=sum/5;if((n==5)||(aver[i]>=90)){ printf("%5d",num[i]);for(k=0;k<5;k++)printf("%10.2f",score[i][k]);printf("%10.2f\n",aver[i]);}}}(6)/*习题9-4-6*/#include <math.h>double sigma(double (*fn)(double),double l,double u){ double sum=0,d;for(d=l; d<u; d+=0.1)sum+=fn(d);return sum;}void main(){ double sum;sum=sigma(sin,0.1,1.0);printf("sum of sin from 0.1 to 1.0 is: %f\n",sum);sum=sigma(cos,0.5,3.0);printf("sum of cos from 0.5 to 3.0 is: %f\n",sum);}(7)/*习题9-4-7 */main(){ int i;char *month_name(int n);printf("input Month No.:\n");scanf("%d",&i);printf("Month No.:%2d --> %s\n",i,month_name(i)); /*调用指针函数month_name()*/ }char *month_name(int n)/*定义一个指针函数month_name()，返回一个指向字符串的指针*/{ static char *name[]={"Illegal Month","January", "February", "March", "April","May", "June", "July", "August","September", "October", "November", "December"};return((n<1||n>12)?name[0]:name[n]);}(8)/*习题9-4-8 */#include <stdio.h>#include <string.h>#define N 10main(){ void sort(char *p[]);int i;char *p[N],str[N][20];for(i=0;i<N;i++)p[i]=str[i]; /*将第i个字符串的首地址赋予指针数组p的第i个元素*/ printf("Input strings:\n");for(i=0;i<N;i++)scanf("%s",p[i]);sort(p);printf("Now, the sequence is:\n");for(i=0;i<N;i++)printf("%s\n",p[i]);}void sort(char *p[]){ int i,j;char *temp;for(i=0;i<N-1;i++)for(j=0;j<N-1-i;j++)if(strcmp(*(p+j),*(p+j+1))>0){ temp=*(p+j);*(p+j)=*(p+j+1);*(p+j+1)=temp;}}(9)/*习题9-4-9 */#include <stdio.h>#define LINEMAX 20 /*定义字符串的最大长度*/main(){ void sort(char **p);int i;char **p,*pstr[5],str[5][LINEMAX];for(i=0;i<5;i++)pstr[i]=str[i]; /*将第i个字符串的首地址赋予指针数组pstr的第i 个元素*/printf("Input 5 strings:\n");for(i=0;i<5;i++)scanf("%s",pstr[i]);p=pstr;sort(p);printf("strings sorted:\n");for(i=0;i<5;i++)printf("%s\n",pstr[i]);}void sort(char **p) /*冒泡法对5个字符串排序的函数*/{ int i,j;char *temp;for(i=0;i<5;i++){ for(j=i+1;j<5;j++){ if(strcmp(*(p+i),*(p+j))>0) /*比较后交换字符串地址*/{ temp=*(p+i);*(p+i)=*(p+j);*(p+j)=temp;}}}}(10)void StrOR(char xx[][80],int maxline){ int i,righto,j,s,k;char temp[80];for(i=0; i<maxline; i++)for(j=strlen(xx[i])-1; j>=0; j--){ k=0; memset(temp,0,80);if(xx[i][j]=='o'){ righto=j;for(s=righto+1; s<strlen(xx[i]); s++)temp[k++]=xx[i][s];for(s=0;s<righto;s++)if(xx[i][s]!='o') temp[k++]=xx[i][s];strcpy(xx[i],temp);}else continue;}}。