13.4
int main(int argc, char *argv[]) {
char ch[20];
int i=0;
FILE *fp;
if((fp=fopen("test.txt","w"))==NULL)
{
printf("cannot open this file\n");
exit(0);
}
scanf("%s",ch);
strupr(ch);
while(ch[i]!='!')
{
fputc(ch[i++],fp);
}
fclose(fp);
}
13.5
int main(int argc, char *argv[]) {
FILE *fp;
char str1[20],str2[20],str[20];
if((fp=fopen("t1.txt","r"))==NULL)
{
printf("Cannot open file A!");
exit(0);
}
fgets(str1,10,fp);
if((fp=fopen("t2.txt","r"))==NULL)
{
printf("Cannot open file B!");
exit(0);
}
int i,j,n;
char t;
fgets(str2,20,fp);
strcat(str1,str2);
strcpy(str,str1);
n=strlen(str);
for(j=0;j<n-1;j++)
for(i=0;i<n-1-j;i++)
if(str[i]>str[i+1])
{
t=str[i];
str [i] = str [i + 1];
str[i+1]=t;
}
if((fp=fopen("C.txt","w"))==NULL)
{
printf("Cannot open C file!");
exit(0);
}
fputs(str,fp);
fputs("\n",fp);
printf("%s\n",str);
return 0;
}
13.6-13.9
struct student//Define the structure
{
int num;
char name[10];
int score[3];
float ave;
}stu[5];
int main(int argc, char *argv[]) {
int i,j,sum,t;
FILE *fp;
struct student p,temp,re[6];
for(i=0;i<5;i++)//Structure assignment
{
printf("Enter the %d record\n",i+1);
scanf("%d,%s",&stu[i].num,stu[i].name);
printf("Please enter the grades of three courses\n");
scanf("%d,%d,%d",&stu[i].score[0],&stu[i].score[1],&stu[i].score[2]);
sum=0;
sum=stu[i].score[0]+stu[i].score[1]+stu[i].score[2];
stu[i].ave=sum/3.0;
}
if((fp=fopen("stud.txt","w"))==NULL)//Write the file
{
printf("cannot open stud.txt\n");
exit(0);
}
for(i=0;i<5;i++)
fwrite(&stu[i],sizeof(struct student),1,fp);
fclose(fp);
if((fp=fopen("stud.txt","r"))==NULL)//Read the file
{
printf("cannot open stud.txt\n");
exit(0);
}
for(i=0;i<5;i++)
{
fread(&stu[i],sizeof(struct student),1,fp);
printf("%d,%s,%d,%d,%d,%6.2f\n",stu[i].num,stu[i].name,stu[i].score[0],stu[i].score[1],stu[i].score[2],stu[i].ave);
}
fclose(fp);
printf("\n");
for(i=0;i<4;i++)//File sorting
for(j=i+1;j<5;j++)
if(stu[i].ave>stu[j].ave)
{
temp = stu [i];
stu [i] = stu [j];
stu[j]=temp;
}
if((fp=fopen("stu_sort.txt","w"))==NULL)
{
printf("cannot open stud.txt\n");
exit(0);
}
for(i=0;i<5;i++)
fwrite(&stu[i],sizeof(struct student),1,fp);
fclose(fp);
if((fp=fopen("stu_sort.txt","r"))==NULL)
{
printf("cannot open stud.txt\n");
exit(0);
}
for(i=0;i<5;i++)
{
fread(&stu[i],sizeof(struct student),1,fp);
printf("%d,%s,%d,%d,%d,%6.2f\n",stu[i].num,stu[i].name,stu[i].score[0],stu[i].score[1],stu[i].score[2],stu[i].ave);
}
fclose(fp);
//insert file
printf("Please enter insert student data:\n");
scanf("%d,%s",&p.num,p.name);
printf("Please enter the grades of three courses\n");
scanf("%d,%d,%d",&p.score[0],&p.score[1],&p.score[2]);
sum=0;
sum=p.score[0]+p.score[1]+p.score[2];
p.ave=sum/3.0;
if((fp=fopen("stu_sort.txt","r"))==NULL)
{
printf("cannot open stud.txt\n");
exit(0);
}
for(i=0;i<5;i++)
{
fread(&stu[i],sizeof(struct student),1,fp);
if(stu[i].ave>p.ave)
{
t=i;break;
}
else
t=5;
}
fclose(fp);
fp=fopen("sdent.txt","a");
if(t==5)
{
for(i=0;i<5;i++)
fwrite(&stu[i],sizeof(struct student),1,fp);
fwrite(&p,sizeof(struct student),1,fp);
}
else if(t==0)
{
fwrite(&p,sizeof(struct student),1,fp);
fwrite(&stu[i],sizeof(struct student),1,fp);
}
else
{
for(i=0;i<t;i++)
fwrite(&stu[i],sizeof(struct student),1,fp);
fwrite(&p,sizeof(struct student),1,fp);
for(i=t;i<5;i++)
fwrite(&stu[i],sizeof(struct student),1,fp);
}
fclose(fp);
//read the inserted file
if((fp=fopen("sdent.txt","r"))==NULL)
{
printf("cannot open stud.txt\n");
exit(0);
}
for(i=0;i<6;i++)
{
fread(&re[i],sizeof(struct student),1,fp);
printf("%d,%s,%d,%d,%d,%6.2f\n",re[i].num,re[i].name,re[i].score[0],re[i].score[1],re[i].score[2],re[i].ave);
}
fclose(fp);
}
13.10-13.11
struct employ//Define the structure
{
char name[10];
int num;
char sex;
int old;
char locate[20];
int money;
char health[6];
char school[20];
}stu[2]={{"zhang",1,'m',30,"yinchuan",8000,"good","master"},{"wang",2,'w',45,"henan",10000,"good","doctor"}};
struct stud//Define salary data structure
{
char name[10];
int money;
}sdent[2];
int main(int argc, char *argv[]) {
FILE *fp;
int i;
fp=fopen("employee.txt","w");//Write data to employee
for(i=0;i<2;i++)
fwrite(&stu[i],sizeof(struct employ),1,fp);
fclose(fp);
fp=fopen("employee.txt","r");//Read the data in the employee and assign a value to the employee salary structure
for(i=0;i<2;i++)
{
fread(&stu[i],sizeof(struct employ),1,fp);
strcpy(sdent[i].name,stu[i].name);
sdent[i].money=stu[i].money;
}
fclose(fp);
fp=fopen("gz.txt","w");//Write data to the employee salary file
for(i=0;i<2;i++)
fwrite(&sdent[i],sizeof(struct stud),1,fp);
fclose(fp);
fp=fopen("gz.txt","r");//Read the data in the employee salary file and verify whether it is written
for(i=0;i<2;i++)
{
fread(&sdent[i],sizeof(struct stud),1,fp);
printf("%s,%d\n",sdent[i].name,sdent[i].money);
}
fclose(fp);
//delete employee salary
fp=fopen("gz.txt","r");//Read the data in the employee salary file and verify whether it is written
for(i=0;i<2;i++)
{
fread(&sdent[i],sizeof(struct stud),1,fp);
// printf("%s,%d\n",sdent[i].name,sdent[i].money);
}
fclose(fp);
fp=fopen("gz.txt","w");//Write data to the employee salary file
for(i=0;i<1;i++)
fwrite(&sdent[i],sizeof(struct stud),1,fp);
fclose(fp);
fp=fopen("gz.txt","r");//Read the data in the employee salary file and verify whether it is written
for(i=0;i<2;i++)
{
fread(&sdent[i],sizeof(struct stud),1,fp);
printf("%s,%d\n",sdent[i].name,sdent[i].money);
}
fclose(fp);
}