linux C上機練習

檔案讀寫操作

fopen  fclose   fgetc   fputc

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#include <stdio.h>#include <stdlib.h>int main(){    FILE * fp;    char ch;    if((fp = fopen("file.txt", "w")) == NULL) //如果檔案不存在，自動建立。 不能少一個括弧！！    {        printf("Cannot open this file!\n");        exit(0);    }    else    {        printf("File open successfully! -----WriteOnly\n");    }        printf("Input character from keyboard and end input with character '#'\n");    while(1)    {        ch = getchar();        if(ch == '#')            break;        else        {            fputc(ch, fp);         }    }    if(fclose(fp) == 0)    {        printf("File write successful and closed\n");    }    if((fp = fopen("file.txt", "r")) == NULL)    {        printf("Cannot open this file!\n");        exit(0);    }    else    {        printf("File open successful-------ReadOnly!\n");    }    printf("Read from this file!\n");    while(1)    {        ch = fgetc(fp);        if(ch != EOF)            printf("%c", ch);        else            break;    }        if(fclose(fp) == 0)    {        printf("\nFile read successful and closed\n");    }}

 fgets   fputs

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#include <stdio.h>#include <stdlib.h>#include <string.h>typedef struct {    char name[10];    char college[20];}student;int main(){    FILE * fp;    student stu;    student stu_read;    if((fp = fopen("file.txt", "w")) == NULL)    {        printf("Cannot open this file!\n");        exit(0);    }    else    {        printf("File open successfully! -----WriteOnly\n");    }        printf("name:");    fgets(stu.name, 10, stdin);    printf("college:");    fgets(stu.college, 20, stdin);    if(fputs(stu.name, fp) != EOF && fputs(stu.college, fp) != EOF)    {        printf("write successful!\n");    }    if(fclose(fp) == 0)    {        printf("File close\n");    }    if((fp = fopen("file.txt", "r"))==NULL)    {        printf("Can not open this file!\n");        exit(0);    }    else    {        printf("File open successfully! -----ReadOnly\n");    }    fgets(stu_read.name, 10, fp);    fgets(stu_read.college, 20, fp);    printf("Student name is %s\n", stu_read.name);    printf("Student college is %s\n", stu_read.college);        if(fclose(fp) == 0)    {        printf("\nFile read successful and closed\n");    }}

 fread  fwrite

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#include <stdio.h>#include <stdlib.h>int main(){    struct student    {        char number[6];        char name[20];        char sex;        int age;        int score;    }    s[2] = {{"00001", "Peter", 'm', 19, 250},{"00002", "Betty", 'f', 18, 268}};    struct student ss[2];    int i, j;    FILE * fp;    if((fp = fopen("file.dat", "wb+")) == NULL)    {        printf("Cannot open this file!\n");        exit(0);    }    j = sizeof(struct student);    for(i = 0; i <= 1; i++)    {        if(fwrite(&s[i], j, 1, fp) != 1)        {            printf("write error!\n");            exit(0);        }    }    fflush(fp);    printf("write successful!\n");    rewind(fp);    printf("Begin to read file...\n");    for(i = 0; i <=1; i++)    {        fread(&ss[i], j, 1, fp);        printf("%s, %s, %c, %d, %d\n", ss[i].number, ss[i].name, ss[i].sex, ss[i].age, ss[i].score);    }    fclose(fp);}