6月12日C代码

//-------------------------------------------1
#include<stdio.h>
#include<stdlib.h>
void main()
{
    FILE *fp;
    int x;
    if((fp=fopen("f1.txt","w+"))==NULL)//打开（创建）文件为写入数据做准备
    {
        printf("Can't open this file!\n");
        exit(1);
    }
    printf("input x:");
    scanf("%d",&x);
    fprintf(fp,"%6d",x);//将变量x中的值写入文件
    fclose(fp);//关闭文件

    if((fp=fopen("f1.txt","r+"))==NULL)//再打开文件为写入数据做准备
    {
        printf("Can't open this file!\n");
        exit(2);
    }
    fscanf(fp,"%d",&x);//由文件读出整数给变量x;
    printf("%6d",x);
    printf("\n");
    fclose(fp);//再关闭文件
}
//---------------------------------------------------------2
/*
打开文件函数fopen().关闭文件函数fclose().
字符读取函数fgetc和fputc
字符串读取函数fgets和fputs
格式化读取函数fscanf和fprintf
数据块读取函数freed和fwrite
检测文件结束函数feof(),eof()
*/
#include<stdio.h>
#include<stdlib.h>
void main()
{
    FILE *fp;//定义文件指针
    char ch,filename[10];//定义字符变量和字符数组，字符数组用来放文件名
    gets(filename);//接受来自键盘输入的文件名
    if((fp=fopen(filename,"w"))==NULL)//打开文件并判断是否成功
    {
        printf("can not open file\n");
        exit(1);//打开文件失败结束过程，exit()函数在stdlib.h中
    }
    printf("Please input string:");
    while ((ch=getchar())!='#')//循环接受字符，并判断是否是结束符
        fputc(ch,fp);//将字符写入文件
        fclose(fp);//关闭文件
}
//-------------------------------------------3
#include"stdio.h"
#include<stdlib.h>
void main()
{
    FILE *in,*out;
    char ch,infile[10],outfile[10];
    scanf("%s",infile);
    scanf("%s",outfile);
    if((in=fopen(infile,"r"))==NULL)
    {
        printf("can not open infile\n");
        exit(1);
    }
        if((out=fopen(outfile,"w"))==NULL)
        {
            printf("cannot open outfile\n");
            exit(1);
        }
        while((ch=fgetc(in))!=EOF)
            fputc(ch,out);
        fclose(in);
        fclose(out);
}
//-------------------------------------4
#include<stdio.h>
#include<string>
void main()
{
    FILE *fp;
    char string[81];//
    if((fp=fopen("file1.txt","w"))==NULL)
    {
        printf("can't open file");
        exit(1);
    }
    while(strlen(gets(string))>0)
    {
        fputs(string,fp);
        fputs("\n",fp);
    }
    fclose(fp);
    if((fp=fopen("file1.txt","r"))==NULL)
    {
        printf("can't open file");
        exit(1);
    }
    while(fgets(string,81,fp)!=NULL)//while（!feof(fp)）

        fputs(string,stdout);//将string指向的字符串输出到stdout(显示器)上
    fclose(fp);
}
//--------------------------------------5
#include<stdio.h>
#include<string>
#define N 10
void main()
{
    FILE *fp;
    int i,x;
    if((fp=fopen("f1.txt","w+"))==NULL)
    {
        printf("Can't open this file!\n");
        exit(1);
    }
    for(i=0;i<N;i++)
    {
        scanf("%d,&x");
        fprintf(fp,"%6d",x);
    }
    fclose(fp);
    if((fp=fopen("f1.txt","r+"))==NULL)
    {
        printf("Can't open this file!\n");
        exit(2);
    }
    for(i=0;i<N;i++)
    {
        fscanf(fp,"%d",&x);
        printf("%6d",x);
    }
    printf("\n");
    fclose(fp);
}
//-----------------------------------------------6
#include<stdio.h>
#include<string>
struct stu
{
    int num;
    char name[10];
    int score[3];
}student;
void main()
{
    int i;
    FILE *fp;
    if((fp=fopen("list1","ab"))==NULL)
    {
        printf("cannot open file\n");
        exit(1);
    }
    printf("student information:\n");
    printf("num:\n");
    scanf("%d",&student.num);
    printf("name:\n");
    scanf("%s",&student.name);
    printf("score1:\n");
    scanf("%d",&student.score[0]);
    printf("score2:\n");
    scanf("%d",&student.score[1]);
    printf("score3:\n");
    scanf("%d",&student.score[2]);
    if(fwrite(&student,sizeof(struct stu),1,fp)!=1)//写一个学生数据块文件
        printf("file write error:\n");
    fclose(fp);
}
//----------------------------------------------------7
#include<stdio.h>
#include<stdlib.h>
#define N 3
struct stu
{
    int num;
    char name[10];
    int score[3];
}students[N];
void main()
{
    FILE*fp;
    int i;
    if((fp=fopen("list ","rb"))==NULL)//以读方式打开二进制文件
    {
        printf("cannot open file!\n");
        exit(1);
    }
    for(i=0;i<N;i++)
    {
        fseek(fp,i*sizeof(struct stu),0);//以起点为基准，按学生数据块移动位置指针
        fread(&students[i],sizeof(struct stu),1,fp);//读出一个学生数据
        printf("%d,%s, %d,%d\n",students[i].num,students[i].name),students[i].score[0],students[i].score[1],students[i].score[2];);
    }
    fclose(fp);
}
//-------------------------------------------8
#include"stdio.h"
main()
{
    FILE *fp1,*fp2;
    char c;
    fp1=fopen("work1","r");
    fp2=fopen("f2.txt","w");
    while((c=getc(fp1))!=EOF)
        putchar(c);//读出work1中的信息并写到屏幕上
    rewind(fp1);//把文件的内部指针移到文件的开始处
    while((c=fgetc(fp1))!=EOF)//读出work1中的信息并写入到f2中
        fputc(c,fp2);
    fclose(fp1);
    fclose(fp2);
}
//-----------------------------------9
#include<stdio.h>
#include<stdlib.h>
#define N 3
struct stu
{
    int num;
    char name[10];
    int score[3];
}student[N];
void main()
{
    FILE*fp;
    int i;
    for(i=0;i<N;i++)
    {
        printf("%d student information:\n");
        printf("num:\n");
        scanf("%d",&students[i].num);
        printf("name:\n");
        scanf("%s",students[i].name);
        printf("score1:\n");
        scanf("%d",students[i].score[0]);
        printf("score2:\n");
        scanf("%d",students[i].score[1]);
        printf("score3:\n");
        scanf("%d",students[i].score[2]);
    }
    if(fwrite(&students,sizeof(struct stu),N,fp)!=N)
        printf("file write error\n");
    fclose(fp);
    if((fp=fopen("list","rb"))==NULL)
    {
        printf("Can't open this file!\n");
            exit(1);
    }
    if(fread(&students,sizeof(struct stu),N,fp)!=N)
        printf("file write error\n");
    for(i=0;i<N;i++)
    {
        printf("%d,%s, %d,%d,%d\n",students[i].num,students[i].name,students[i].score[0],students[i].score[1],students[i].score[2]);
    }
    fclose(fp);
}
//-------------------------------------------10
#include<stdio.h>
#include<stdlib.h>
#define N 3
struct stu
{
    int num;
    char name[10];
    int score[3];
}students[N];
void main()
{
    FILE*fp;
    int i;
    for(i=0;i<N;i++)
    {
        printf("%d student information:\n");
        printf("num:\n");
        scanf("%d",&students[i].num);
        printf("name:\n");
        scanf("%s",students[i].name);
        printf("score1:\n");
        scanf("%d",students[i].score[0]);
        printf("score2:\n");
        scanf("%d",students[i].score[1]);
        printf("score3:\n");
        scanf("%d",students[i].score[2]);
    }
    if((fp=fopen("data.txt","w+"))==NULL)
    {
        printf("Can't open this file!\n");
        exit(1);
    }
    for(i=0;i<N;i++)
    {
        printf("%d,%s, %d,%d,%d\n",students[i].num,students[i].name,students[i].score[0],students[i].score[1],students[i].score[2]);
    }
    fclose(fp);
}