经典c语言笔试题.doc

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1、100、有两个磁盘文件A和B,各存放一行字母，要求把这两个文件中的信息合并（按字母顺序排列），输出到一个新文件C中.#include#includeintmain(intargc,char*argv[]){ FILE*fp; inti,j,k,num,NUM; charc[50],t,ch; if((fp=fopen("A","r"))==NULL)   /*canbereplacedbyopen    *intfd=open("A",O_RDONLY

2、O_CREAT);*/   

3、  {       printf("fileAcannotbeopened");       exit(0);     } printf("Acontentsare:"); for(i=0;(ch=fgetc(fp))!=EOF;i++)/*一个字符一个字符读*/  {      c[i]=ch;      putchar(c[i]);  } num=i+1; fclose(fp);if((fp=fopen("B","r"))==NULL)  {     printf("fileBcannotbeopene

4、d");     exit(0);  } printf("Bcontentsare:");for(i=0;(ch=fgetc(fp))!=EOF;i++) {    c[num+i]=ch;    putchar(c[num+i]);  }fclose(fp);NUM=num+i+1;for(k=0;kc[j+1])             {         t=c[j];   

5、      c[j]=c[j+1];         c[j+1]=t;               }   } }printf("Cfileis:");fp=fopen("C","w");for(i=0;i

6、序法)#include#includevoidBubbleSort(intarr[],intn){ inti,j; intexchange=1;//交换标志,提高算法效率； inttemp; for(i=0;iarr[j])    

7、                                 {                temp=arr[j+1];                arr[j+1]=arr[j];                arr[j]=temp;                exchange=1;//发生了交换，故将交换标志置为真                                        }                  }      if(!exchange)//本趟排序未发生交换，提前终

8、止算法       return;         }}intmain(intargc,char*argv[]) {  intarr[5]={1,4,2,6,5};  inti;  BubbleSort(arr,5);  printf("aftersort,arris:");  for(i=0;i<5;i++)           {      printf("%3d",arr[i]);             }  return1;  }77.写出二分查找的代码：  Intbinary_search(int*ar

9、r,intkey,intsize){    Intmid;    Intlow=0;Inthigh=size-1;While(low<=high)    {      Mid=(low+high)/2;      If(arr[mid]>key)          High=mid-1;      ElseIf(arr[mid]<