C语言实验报告答案

二、编程题(参考答案)1、#include “stdio.h”void main(){ int Math=82,eng=78,comp=91,average;average=(Math+eng+comp)/3;printf(“Math=%d,eng=%d,comp=%d,average=%d\n”,Math,eng,comp,average);}2、#include “stdio.h”void main(){ int n=152,d1,d2,d3;d1=n%10;d2=(n/10)%10;d3=n/100;printf(“整数%d的个位数字是%d，十位数字是%d，百位数字是%d\n”,n,d1,d2,d3); }3、#include “stdio.h”void main(){ int n1,n2;printf(“Enter n1,n2：”);scanf(“%d,%d”,&n1,&n2);printf(“%d+%d=%d\n”,n1,n2,n1+n2);printf(“%d/%d=%d\n”,n1,n2,n1/n2);printf(“%d%%%d=%d\n”,n1,n2,n1%n2);}三、改错题原错误行（共三行）：/********************************** found ********************************/#include “stdoi,h”/********************************** found ********************************/ printf(“%d=%d*%d\n”,x);/********************************** found ********************************/ printf(“%d*%d=%d\n”,y);改正后：#include “stdio.h”printf(“%d=%d*%d\n”,y,x,x);printf(“%d*%d=%d\n”,x,x,y);一、改错题1、原错误行（共三行）：/********************************** found ********************************/ #include “stdoi,h”/********************************** found ********************************/ scanf(“%lf”,x);/********************************** found ********************************/ y=1/x改正后：#include “stdio.h”scanf(“%lf”,&x);y=1/x;2、原错误行（共两行）：/********************************** found ********************************/ { int i,sum;/********************************** found ********************************/ for(i=1,i<=100,i++)改正后：{ int i,sum=0;for(i=1;i<=100;i++)二、编程题（本标题报告上漏印了）2、（因为报告上小题号就是从2开始的，没有第1题）#include “stdio.h”#include “math.h”void main(){ int a,b,c;float s,area,perimeter;printf(“请输入三角形的三边：”);scanf(“%d,%d,%d”,&a,&b,&c);if(a+b>c&&a+c>b&&b+c>a){ perimeter=a+b+c;s=perimeter/2;area=sqrt(s*(s-a)*(s-b)*(s-c));printf(“area =%.2f,perimeter=%.2f\n”,area,perimeter);}elseprintf(“不构成三角形”);}3、#include “stdio.h”void main(){ int i,m,n;float sum=0;printf(“Enter m：”);scanf(“%d”,&m);printf(“Enter n：”);scanf(“%d”,&n);for(i=m;i<=n;i++)sum=sum+1.0/i;printf(“sum=%.3f\n”,sum);}4、#include “stdio.h”void main(){ int i,n;float sum=0;printf(“Enter n：”);scanf(“%d”,&n);for(i=1;i<=n;i++)sum=sum+1.0/(2*i-1);printf(“sum=%.2f\n”,sum);}5、#include “stdio.h”void main(){ int i,m,n;long a=1,b=1;printf(“Enter m：”);scanf(“%d”,&m);printf(“Enter n：”);scanf(“%d”,&n);for(i=1;i<=m;i++)a=a*i;for(i=1;i<=n;i++)b=b*i;printf(“%d!+%d!=%ld\n”,m,n,a+b); }实验三一、改错题原错误行（共三行）：/********************************** found ********************************/ double sum;/********************************** found ********************************/ for(i=1;i<10;i++)sum=sum+fact(i);printf(“1!+2!+…+10!=%f\n”,sum);}/********************************** found ********************************/ double fact(int n);改正后：double sum=0;for(i=1;i<=10;i++)double fact(int n)二、编程题1、int even(int n){ if(n%2==0)return 1;elsereturn 0;}2、int prime(int x){ int n;for(n=2;n<x;n++)if(x%n==0)return 0;if(x>=2)return 1;elsereturn 0;}3、#include “stdio.h”int fun1(int n){ if(n%2==0)return 1;elsereturn 0;}int fun2(int x){ int n;for(n=2;n<x;n++)if(x%n==0)return 0;if(x>=2)return 1;elsereturn 0;}void main(){ int i,m,n,a,b;printf(“Enter m：”);scanf(“%d”,&m);printf(“Enter n：”);scanf(“%d”,&n);a=fun1(m);b=fun2(n);if(a==1) printf(“%d是偶数\n”,m);else printf(“%d是奇数\n”,m);if(b==1) printf(“%d是素数\n”,n);else printf(“%d不是素数\n”,n); }实验四一、改错题1、原错误行（共两行）：/********************************** found ********************************/ { int i,s;/********************************** found ********************************/ if(str[i]<=’0’||str[i]>=’9’)改正后：{ int i,s=0;if(str[i]>=’0’&&str[i]<=’9’)2、原错误行（共三行）：/********************************** found ********************************/ { int i,j,n,x,a[n];/********************************** found ********************************/ a[i] =a[i+1];/********************************** found ********************************/ a[i]=x; /*插入改正后：{ int i,j,n,x,a[10];a[i+1] =a[i];a[j]=x;3、原错误行（共三行）：/********************************** found ********************************/ max=str;/********************************** found ********************************/ if(max<str)/********************************** found ********************************/ max=str;改正后：strcpy(max,str);if(strcmp(max,str)<0)strcpy(max,str);4、原错误行（共两行）：/********************************** found ********************************/ void fun(int a[],int n) /*该函数求出a数组中n个元素奇数的个数*//********************************** found ********************************/ if(a[i]%2==0) m++;改正后：int fun(int a[],int n)if(a[i]%2!=0) m++;二、编程题1、#include “stdio.h”void main(){ int i,n,min,max,s1,s2,t,a[10];printf(“请输入数据个数n值：”);scanf(“%d”,&n);printf(“请输入这%d个数：”,n);for(i=0;i<n;i++)scanf(“%d”,&a[i]);min=a[0]; s1=0;max=a[n-1]; s2=n-1;for(i=0;i<n;i++){ if(a[i]<min) { min=a[i]; s1=i; }if(a[i]>max) { max=a[i]; s2=i; }}if(s1!=0) { t=a[0];a[0]=a[s1];a[s1]=t; }if(s2!=n-1) { t=a[n-1];a[n-1]=a[s2];a[s2]=t; } for(i=0;i<n;i++)printf(“%d ”,a[i]);}2、int sum(int a[],int n){ int i,sum=0;for(i=0;i<n;i++)sum+=a[i];return sum;}实验五一、改错题1、原错误行（共两行）：/********************************** found ********************************/ scanf(“%d”,&p++);/********************************** found ********************************/ x[0]=x[k];改正后：scanf(“%d”,p++);x[0]=k;二、编程题1、int search(int *a,int n,int x){ int i;for(i=0;i<n;i++)if(a[i]==x) return i;return -1;}2、int fun(char *s){ int i,j,n；n=strlen(s);for(i=0,j=n-1;i<n/2;i++,j--)if(s[i]!=s[j])return 0;return 1;}3、此题为选作题#include “stdio.h”void sort(int *a,int n){ int i,j,k,t;for(i=0;i<n-1;i++){ k=i;for(j=i+1;j<n;j++)if(a[j]<a[k]) k=j;if(k!=i){ t=a[i];a[i]=a[k];a[k]=t; }}}main(){ int a[10],i,n;printf(“请输入n值：”);scanf(“%d”,&n);printf(“请输入这%d个元素值：”,n);for(i=0;i<n;i++)scanf(“%d”,&a[i]);sort(a,n);for(i=0;i<n;i++)printf("%d ",a[i]);printf("\n");}实验六一、改错题（原错误行共两行）：/********************************** found ********************************/ { scanf(“%d”,&score[j]);/********************************** found ********************************/ printf("总分最高的学生是：%s,%d\n", name, sum);改正后：{ scanf(“%d”,&a[i].score[j]);printf("总分最高的学生是：%s,%d\n", a[k].name, a[k].sum);二、编程题1、#include "stdio.h"typedef struct student /*定义结构体类型*/{ long num;char name[9];int score[3];float aver;}STU;void main(){ STU a[10];int i,j,n,s=0;printf("输入n：");scanf("%d",&n);for(i=0;i<n;i++){ printf("输入第%d个学生的学号、姓名和3门课成绩：",i+1);scanf("%ld",&a[i].num);scanf("%s",a[i].name);s=0;for(j=0;j<3;j++){ scanf("%d",&a[i].score[j]); s+=a[i].score[j]; }a[i].aver=s/3.0;}for(i=0;i<n;i++)printf("%s,%.2f分\n",a[i].name,a[i].aver);}三、填空题p->next= head ;head= p ;}p=head ;实验七一、改错题（原错误行共两行）：/********************************** found ********************************/ FILE fp;/********************************** found ********************************/ if((fp=fopen(“a.txt”,“w”))!=NULL)改正后：FILE *fp;if((fp=fopen(“a.txt”,“w”))==NULL)二、编程题1、#include "stdio.h"#include "string.h"void main(){ FILE *fp;char a[10];if((fp=fopen("test.txt","w"))==NULL){ printf("error");exit(0);}scanf("%s",a);strupr(a);fputs(a,fp);fclose(fp);}2、#include "stdio.h"#include "string.h"void main(){ FILE *fp;char a;if((fp=fopen("test.txt","r"))==NULL){ printf("error");exit(0);}while(!feof(fp)){ a=fgetc(fp);printf("%c",a);}fclose(fp);}3、#include "stdio.h"#include "stdlib.h"typedef struct student{ long num;char name[9];int score[3];float aver;}STU;void main(){ FILE *fp;int i,j,n,s;STU a;scanf("%d",&n);if ((fp=fopen("stud.dat","wb"))==NULL){ printf("File connot be opened\n");exit(0);}for(i=1;i<=n;i++){ scanf("%ld",&a.num);scanf("%s",);s=0;for(j=0;j<3;j++){ scanf("%d",&a.score[j]); s+=a.score[j]; }a.aver=s/3.0;fwrite(&a,sizeof(STU),1,fp);}fclose(fp);}4、#include "stdio.h"#include "stdlib.h"typedef struct student{ long num;char name[9];int score[3];float aver;}STU;void main(){ FILE *fp;int i,j,n,s;STU a;if ((fp=fopen("stud.dat","rb"))==NULL){ printf("File connot be opened\n");exit(0);}while(fread(&a,sizeof(STU),1,fp)!=NULL){ printf("%ld\t%s\t",a.num,);printf("%d\t%d\t%d\t%.2f\n",a.score[0],a.score[1],a.score[2],a.aver);}fclose(fp);}。