9.9设计程序,从上题生成的文件中读入学生的考试成绩,求每门课的平均成绩和每个 人的平均成绩 解:请参考习题89,本例只求出单科的平均成绩。参考程序如下: #include <stdio. h #define n 50 typedef struct student char name double score void pnt(student *stup int n I int i, k, fl: double sum printf( Output is \n") for(i=0; i<n: i++) printf(%12s", (stup+i)->name printf(%5. llf",(stup+i)->score) printf( " \n") I student stu[N] Int l,n ILE *in double ave, sumO printf( Enter file name: \n") if ((in=fopen(fname, "rb))==NULL) i printf("cannot open file \n") exit(O) n=fread(stu, sizeof (student), N, in)fclose(out); } 9.9 设计程序，从上题生成的文件中读入学生的考试成绩，求每门课的平均成绩和每个 人的平均成绩。 解：请参考习题 8.9，本例只求出单科的平均成绩。参考程序如下： #include <stdio.h> #define N 50 typedef struct student { char name[10]; double score; } student; void pnt(student *stup,int n) { int i,k,flag; double sum; printf("Output is \n"); for (i=0;i<n;i++) { printf("%12s",(stup+i)->name); printf("%5.1lf ",(stup+i)->score); printf("\n"); } } main() { student stu[N]; int i,n; FILE *in; char fname[50]; double ave,sum=0; printf("Enter file name:\n"); scanf("%s",fname); if ((in=fopen(fname,"rb"))==NULL) { printf("cannot open file \n"); exit(0); } n=fread(stu,sizeof(student),N,in); pnt(stu,n);