谭浩强C语言（第二版）第十三章课后答案

柔光的暖阳◎ 2022-05-26 00:48 260阅读 0赞

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);	
    }