C语言编程课后训练20道题

C语言编程课后训练20道题/*-------------------------------------------------------【程序填空】---------------------------------------------------------

功能：下面函数为二分法查找key值。数组中元素已递增排序， 若找到key则返回对应的下标，否则返回-1。

-------------------------------------------------------*/#include fun(int a[],int n,int key){ int low,high,mid; low=0; high=n-1; /***********SPACE***********/ while(【?】) { mid=(low+high)/2; if(keya[mid]) /***********SPACE***********/ 【?】; else /***********SPACE***********/ 【?】; } return -1;}main(){ int a[10]={1,2,3,4,5,6,7,8,9,10}; int b,c; b=4; c=fun(a,10,b); if(c==1) printf("not found"); else printf("position %d\n",c);}

标准答案：low<=high high=mid-1 low=mid+1 return mid

/*------------------------------------------------【程序设计】--------------------------------------------------

功能：编写函数fun求1!+2!+3!+ …… +n!的和,在main函 数中由键盘输入n值，并输出运算结果。请编写fun 函数。例如：若n值为5，则结果为153。

------------------------------------------------*/ #includevoid wwjt(); long int fun(int n){ /**********Program**********/

/********** End **********/ }

main(){ int n; long int result; scanf("%d",&n); result=fun(n); printf("%ld\n",result); wwjt();}

void wwjt(){FILE *IN,*OUT; int i; int iIN; long int iOUT; IN=fopen("in.dat","r"); if(IN==NULL) { printf("Please Verify The Currernt Dir..It May Be Changed"); } OUT=fopen("out.dat","w"); if(OUT==NULL) { printf("Please Verify The Current Dir.. It May Be Changed"); } for(i=0;i<10;i++) { fscanf(IN,"%d",&iIN); iOUT=fun(iIN); fprintf(OUT,"%ld\n",iOUT); } fclose(IN); fclose(OUT);}

标准答案： int i,j,s,t=0; for(i=n;i>0;i--) {s=1; for(j=1;j<=i;j++) s=s*j; t=t+s;} return t;

/*-------------------------------------------------------【程序填空】---