C语言程序设计实验与习题答案

2．程序填空(1)以下程序的功能是计算1~50之间能被7整除的整数之和。

#include<>void main(){int i,sum= 0;for(i=1;50;i++)if(i%7==0) sum+=i;printf("sum=%d\n",sum);}(2) 下面程序接收来自键盘的输入，直到输入<Ctrl>+Z(值为-1)键为止。

这些字符被原样输出，但若有连续一个以上的空格时只输出一个空格。

请填空。

#include <>void main(){char cx;char front=’’;while ((cx=getchar())!=’\n’){if (cx!=’’)putchar(cx);if (cx= =’’)if (front!=’’)putchar(cx);front=cx;}}3．程序改错(1)下列程序的功能是求1+3+5+…99的和。

#include <>void main( ){ int s,i; ★10.6f10.6f10.6f10.6f代表个数*/for(i=1;i<=9;i++)for(j=0;j<=9;j++)for(k=0;k<=9;k++)if(i*i*i+j*j*j+k*k*k==1099) /*在所有组合中找出满足指定条件的*/{printf("%4d",100*i+10*j+k);n++;if(n%5==0) printf("\n"); /*表示每行输出5个数*/}}#include<>#include<>main(){int i,j,k;for(i=1;i<=4;i++) /*上三角形有4行,每循环1次输出1行*/{for(k=1;k<8-((2*i-1)/2);k++) /*该循环输出每行的空格.8用于调节偏离位置，可换成别的数（>=8）*/printf(" ");for(j=1;j<=2*i-1;j++) /*该循环输出每行的’*’字符*/printf("*");putchar(’\n’);/*换行*/for(i=3;i>=1;i--) /*下面为倒三角形,有3行*/ {for(k=1;k<8-((2*i-1)/2);k++)printf(" ");for(j=1;j<=2*i-1;j++)printf("*");putchar(’\n’);}}main( ){ int n=1,score,t;scanf("%d",&score);while (score>=0&&n<=5){ n++;t=0;while(score!=0){t=t+(score%10)*(score%10);score=score/10;}if(t==108)printf("%d",score);scanf("%d",&score);}}#include ""main(){float x0,x1,x2,fx0,fx1,fx2; /*x1,x2分别表示每次区间的左右端点,x0代表区间的中间点,fx0,fx1,fx2代表相应点的函数值*/do{printf("please input x1&x2:");scanf("%f,%f",&x1,&x2);fx1=x1*((2*x1-4)*x1+3)-6;fx2=x2*((2*x2-4)*x2+3)-6;}while(fx1*fx2>0); /*该循环指定有根的区间*/do{x0=(x1+x2)/2;fx0=x0*((2*x0-4)*x0+3)-6;if((fx0*fx1)<0) /*丢掉右区间*/{x2=x0;fx2=fx0;}else /*丢掉左区间*/{x1=x0;fx1=fx0;}}while(fabs(fx0)>1e-5); /*该循环实现二分法求根*/printf("root x=%f",x0);}2)程序填空（1）#include <>void main(){int m,n,num1,num2,temp;printf("Input two positive integer:\n");scanf("%d,%d",&num1,__&num2_______);if(num1<num2){temp=num1; num1=num2; num2=__temp_______;}m=num1;n=num2;while(n!=0){ temp=__m%n__________;m=n;n=temp;}printf("The grestest common divisor is %d\n",m);printf("The lowest common multiple is %d\n",num1*num2/__m____); }(2)下面程序是计算表达式1+(1+2)+(1+2+3)+…+(1+2+3+…+10)和。

#include<>void main(){int sum,i,j,t;sum=①;for(i=1;i<=10;i++){t=0;for(j=1;j<=②;j++)t=t+j;sum=③;}printf("1+（1+2）+（1+2+3）+...+（1+2+3+ (10)=%d\n",sum);}①0 ②i ③sum+t3．程序改错(1)下面的程序是求1～100之间的素数，并将所有素数按每行10个输出。

#include <>#define <>★10.3f⑴①a[10]=x;②break;③a[k]=x;附：算法简析main(){int x,i,j,k;/*感觉似乎j定义了没什么作用*/int a[11]={8,18,28,38,48,58,68,78,88,98};printf("请输入需要插入的一个整数：");scanf("%d",&x);a[10]=x;/*把x放到数据串最末位置*/for(i=0;i<10;i++)if(x<a[i]) {k=i;break;}/*寻找x的插入点，当发现插入点时退出*/for(i=10;i>k;i--)/*将插入点以及其后的每个数据后移一个单位（给x腾位）*//*实例演示——腾位8 18 28 38 48 58 68 78 88 98 （x）8 18 28 38 38 48 58 68 78 88 98↑插入点*/a[i]=a[i-1];a[k]=x;/*将x放到插入点位置*/for (i=0;i<11;i++)printf("%3d",a[i]);printf("\n");}⑵①i%7==0||i%11==0②n++③i%5==03.⑴a.将continue;改为break;b.将i=k-1;改为j=k-1;c.将j=k+1;改为i=k+1;d.将for(i=0;i<10;i++)改为for(i=0;i<9;i++);附：算法简析#include <>void main(){int x, i,j,k;int a[10]={ 8,18,28,38,48,58,68,78,88,98};printf("请输入需要删除的一个整数：");scanf("%d",&x);i=0;j=9;while(i<=j){k=(i+j)/2 ;if(a[k]==x) break;if(a[k]>x)j=k-1;if(a[k]<x)i=k+1;}/*二分法查找x在数组中的位置，该位置即删除点，注意始末坐标不要弄颠倒*/if(i>j) printf("需要删除的数不在数组中\n");else{ for( ;k<9;k++)a[k]=a[k+1];/*挤位，后面的数据向删除点靠拢*//*实例演示——挤位（若删除38）删除点↓8,18,28,38,48,58,68,78,88,988,18,28,48,58,68,78,88,98,98*/for (i=0;i<9;i++)/*删除一个数，只剩9个，数组最末尾储存的是重复的数据（倒数第二个），故不输出*/printf("%5d",a[i]);}}⑵a.将for(i=0,j=0;i<=10;i++)改为for(i=1,j=0;i<=10;i++)b.将if(i%3=0)改为if(i%3==0)c.将for(;j>=0;j++)改为for(;j>=0;j--) 4.⑴#include<>#include<>int isprime(int x){int k=sqrt(x);for(;k>1;k--)if(x%k==0) return 0;return x;}void sort(int a[],int x){int i,k,t;for(i=0;i<x-1;i++)for(k=i+1;k<x;k++)if(a[i]>a[k]){t=a[i];a[i]=a[k];a[k]=t;}}void main(){int num[50],prime[50],i,n=0,j;printf("PLease input 50 integers:\n");for(i=0;i<50;i++){scanf("%d",&num[i]);if((j=isprime(num[i]))!=0)prime[n++]=j;}sort(prime,n);printf("The sorted prime numbers are : \n"); for(i=0;i<n;i++)printf("%-5d",prime[i]);}⑵#include<>#include<>main(){char input[10],paswor[10]="password",ch,flag=0;int count=1,i=0;while(count<=3){printf("请输入密码:");while((ch=getch())!=13){input[i++]=ch;putchar(’*’);}input[i]=’\0’;if(strcmp(input,paswor)==0){printf("\n\n你好！我的主人！");flag=1;break;}elseprintf("\n\n离我远点！");count++;getch();}if(flag==0)printf("密码输入三次错误，你不是我的主人！\n\n离我远点！\n\n 否则，我很生气，后果很严重!!!");getch();}⑶main(){int num[10],i,max,min,maxj,minj;printf("Please input the data:\n");scanf("%d",&num[0]);max=min=num[0];for(i=1;i<10;i++){ scanf("%d",&num[i]);if(max<num[i]){max=num[i];maxj=i;}if(min>num[i]){min=num[i];minj=i;}}printf("The maximum element’s underside is %d,max=%d",maxj,num[maxj]); printf("\nThe minimum element’s underside is %d,min=%d",minj,num[minj]); }⑷#include<>#include<>void input(int a[],int *n){int i;printf("How many datas do you want to input ");scanf("%d",n);printf("\nPlease input %d datas:\n",*n);for(i=0;i<*n;i++)scanf("%d",&a[i]);}void sort(int a[],int n){int i,j,t;for(i=0;i<n-1;i++)for(j=i+1;j<n;j++)if(a[i]>a[j]){t=a[i];a[i]=a[j];a[j]=t;}}void menu(int a[],int n){int i;gotoxy(1,24);printf("Datas: ");for(i=0;i<n;i++)printf("%-3d",a[i]);gotoxy(1,1);printf("MENU\n");printf("************************\n");printf("**\n");printf("* a data*\n");printf("**\n");printf("* a data*\n");printf("**\n");printf("* a data*\n");printf("**\n");printf("**\n");printf("**\n");printf("************************\n");printf("PLease input a command==>");}void find(int a[],int n){int x;int low=0,high=n-1,mid;printf("\nPLease input a data to be searched: ");scanf("%d",&x);while(low<=high){mid=(low+high)/2;if(x==a[mid]) break;else if(x>a[mid]) low=mid+1;else high=mid-1;}if(low>high) printf("\nThis data can’t be found in the database!"); else{printf("\nThis data is in the position %d",mid);gotoxy(7+3*(mid+1)-2,23);putchar(25);}}void insert(int a[],int n){int x,k,i;printf("\nPLease input a data to be inserted:");scanf("%d",&x);a[n]=x;for(i=0;i<n;i++)if(x<a[i]) {k=i;break;}for(i=n;i>k;i--)a[i]=a[i-1];a[k]=x;gotoxy(1,24);delline();printf("Datas: ");for(i=0;i<=n;i++)printf("%-3d",a[i]);}void Delete(int a[],int n){int x,low,high,mid,i;printf("\nPLease input a data to be deleted:");scanf("%d",&x);low=0;high=n-1;while(low<=high){mid=(low+high)/2 ;if(a[mid]==x) break;if(a[mid]>x)high=mid-1;if(a[mid]<x)low=mid+1;}if(low>high) printf("The data to be deleted is not in the database!\n");else{for( ;mid<n-1;mid++)a[mid]=a[mid+1];gotoxy(1,24);delline();printf("Datas: ");for(i=0;i<=n-2;i++)printf("%-3d",a[i]);}}main(){int a[50],n=0;char com;input(a,&n);sort(a,n);clrscr();menu(a,n);com=getch();switch(com){case ’1’:find(a,n);break;case ’2’:insert(a,n);break;case ’3’:Delete(a,n);break;default: break;}getch();}/*DT made it in 2009/05/16*/程序填空：（1）#include <>#define N 4void main(){ int a[N][N],s1=0,s2=1,max,i,j;for(i=0; i<N; i++)for(j=0; j<N; j++)scanf("%d", &a[i][j]);max= a[0][0];for(i=0;i<N;i++)for(j=0; j< N ;j++){if(i==j) s1=s1+a[i][j];if(i+j==N-1) s2*=a[i][j];if(a[i][j]> max )max=a[i][j];}printf("s1=%d,s2=%d,max=%d\n",s1,s2,max); }（2）#include<>#define M 4#define N 3void main( ){int a[M][N]={{1,2,3},{4,5,6},{7,8,9},{10,11,12}};int sum= 0,i,j;for(i=0;i<N;i++)sum+=a[0][i]+ a[M-1][i];for(j=1;j<M-1;j++)sum+=a[j][0]+ a[j][N-1] ;printf("%d\n",sum);}改错：（1）#in#include<>#define M 3#define N 4void main( ){int a[M][N]={{1,2,3,4},{5,6,7,8 },{9,10,11,12}}; int b[N][M];int i,j;for(i=0;i<M;i++){for(j=0;j<N;j++)printf("%3d",a[i][j]);printf("\n");}for(i=0;i<N;i++)for(j=0;j<M;j++)b[i][j]=a[j][i];printf("\n");for(i=0;i<N;i++){for(j=0;j<M;j++)printf("%3d",b[i][j]);printf("\n");}}（2）#include<>void main(){int d[][4] ={{0,0,0,0}},i,j;printf("\nPlease input 16 num: ");for(i=0;i<4;i++)for(j=0;j<4;j++)scanf("%d",&d[i][j]);for(i=0;i<4;i++)for(j=0;j<4;j++)if(d[i][j]<d[j][i])d[i][j]=d[j][i];for(i=0;i<4;i++){printf("\n\n\n\n\n");/*为了保持每行的间隔与每列的相同*/for(j=0;j<4;j++)if(j>=i)printf("\t%d",d[i][j]);/*为了使位数不同的数输出依然保持三角型*/ elseprintf("\t");}}设计性实验：（1）#include<>#define M 3#define N 6{int i,j,max,min,m=0,n=0,p=0,q=0;int a[M][N];for(i=0;i<M;i++)for(j=0;j<N;j++)scanf("%d",&a[i][j]);max=min=a[0][0];for(i=0;i<M;i++)for(j=0;j<N;j++){ if(a[i][j]>max){max=a[i][j];m=i;n=j;}else if(a[i][j]<min){ min=a[i][j];p=i;q=j;}}printf("max(%d,%d)=%d,min(%d,%d)=%d",m,n,max,p,q,min);}（3）#include<>void main(){int n,i,j;int a[N][N];printf("please input the n:");scanf("%d",&n);for(i=0;i<n;i++){a[i][0]=1;a[i][i]=1;}for(i=2;i<n;i++)for(j=1;j<i;j++)a[i][j]=a[i-1][j-1]+a[i-1][j];for(i=0;i<n;i++){for(j=0;j<=i;j++)printf("%-4d",a[i][j]);printf("\n");}}2．程序填空(1)以下程序的功能是求数组a中元素的和。