谭浩强C语言（第二版）第十三章课后答案

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("无法打开A文件！");  
        exit(0);  
    }  
    fgets(str1,10,fp);  
    if((fp=fopen("t2.txt","r"))==NULL)  
    {  
        printf("无法打开B文件！");  
        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("无法打开C文件！");  
        exit(0);  
    }  
    fputs(str,fp);  
    fputs("\n",fp);  
    printf("%s\n",str);  
    return 0;
}

13.6-13.9

struct student//定义结构体 
{
	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++)//结构体赋值 
	{
		printf("输入第%d条记录\n",i+1);
		scanf("%d,%s",&stu[i].num,stu[i].name);
		printf("请输入三门课成绩\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)//写入文件 
	{
		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)//读取文件 
	{
		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++)//文件排序 
    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);
    
    //插入文件
	printf("请输入插入学生数据：\n");
	scanf("%d,%s",&p.num,p.name);
	printf("请输入三门课成绩\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);
//读取插入后文件
	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//定义结构体 
{
	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//定义工资数据结构体 
{
	char name[10];
	int money;
}sdent[2];

int main(int argc, char *argv[]) {
	FILE *fp;
	int i;
	fp=fopen("employee.txt","w");//向employee中写入数据 
	for(i=0;i<2;i++)
	fwrite(&stu[i],sizeof(struct employ),1,fp);
	fclose(fp);
	fp=fopen("employee.txt","r");//读取employee中数据，并对职工工资结构体赋值 
	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");//向职工工资文件中写入数据 
	for(i=0;i<2;i++)
	fwrite(&sdent[i],sizeof(struct stud),1,fp);
	fclose(fp);
	fp=fopen("gz.txt","r");//读取职工工资文件中数据，验证是否写入 
	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);
	
	//职工工资删除
	 
 	fp=fopen("gz.txt","r");//读取职工工资文件中数据，验证是否写入 
	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");//向职工工资文件中写入数据 
	for(i=0;i<1;i++)
	fwrite(&sdent[i],sizeof(struct stud),1,fp);
	fclose(fp);
	
	fp=fopen("gz.txt","r");//读取职工工资文件中数据，验证是否写入 
	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);	
}