经典c语言笔试题经典c语言笔试题.doc

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. #includestdio.h #includestdlib.hint main(int argc,char* argv[]){? FILE* fp;? int i,j,k,num,NUM;? char c[50],t,ch;?if((fp=fopen(A,r))==NULL)?? ? /*can be replaced by open?? ?? * int fd=open(A,O_RDONLY|O_CREAT);*/????? {?? ??? ?? printf(fileA cannot be opened\n);?? ??? ?? exit(0);????? }?printf(\nA contents are:\n);?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(fileB cannot be opened\n);?? ??? exit(0);?? }?printf(\nB contents are :\n);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;kNUM-1;k++)/*冒泡排序*/? {?? ?for(j=0;jNUM-k-1;j++)?? ?{?? ??? ?if(c[j]c[j+1])????????????? {?? ??????? t=c[j];?? ??????? c[j]=c[j+1];?? ??????? c[j+1]=t;??????????????? }?? ?}? }printf(\nC fileis:\n);fp=fopen(C,w);for(i=0;iNUM;i++){?? ?putc(c[i],fp);/*将字符一个个写入文件中*/?? ?putchar(c[i]);/*一个个输出字符*/}fclose(fp);return 1;} 86.有一浮点型数组A,用C语言写一函数实现对浮点数组A进行降序排序,并输出结果,要求要以数组A作为函数的入口.(建议用冒泡排序法) #includestdio.h#includestdlib.hvoid BubbleSort(int arr[], int n){? int i,j;? int exchange = 1;//交换标志,提高算法效率；? int temp;? for(i=0;in-1;i++)? ?? ? ??? ?? {?????? exchange=0;//本趟排序开始前，交换标志应为假?????? for(j=0;jn-i-1;j++)???????????????????????? {??????????? if(arr[j+1] arr[j])????????????????????????????????????? {???????????????? 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，提前终止算法??????? return;????????? }}int main(int argc,char* argv[])? {?? int arr[5]={1,4,2,6,5};?? int i;?? BubbleSort(arr, 5);?? printf(after sort,arr is :\n);?? for(i=0;i5;i++)??????????? {?????? printf(%3d,arr[i]);????????????? }?? return 1;?? } 77.写出二分查找的代码：