文件操作库函数的使用 _0304

//fopen.c

//文件操作3步曲：
//              fopen打开要操作的文件
//              用文件操作库函数实现对文件的操作
//              fclose关闭文件

//用fgets函数，获得文件的一行(知道遇到'\n')
//fputs函数，输出文件的一行

#include <stdio.h>

int main(int argc, const char *argv[])
{
    FILE *fp;
    char buff[128];

    if((fp = fopen("1.c", "a")) == NULL)
        printf("open failure\n");

    fgets(buff, sizeof(buff), stdin);

    fputs(buff, fp);


    fclose(fp);
    return 0;
}

//fgetc_fputc_cp.c

//用fgetc函数，实现copy函数功能

#include <stdio.h>

void copy(char *src, char *dest)
{
    FILE *fp1, *fp2;
    char ch;

    fp1 = fopen(src, "r");
    fp2 = fopen(dest, "w");
    if((fp1 == NULL) || (fp2 == NULL))
        printf("%s/%s open failure\n", src, dest);

    while((ch = fgetc(fp1)) != EOF)
        fputc(ch, fp2);
    fclose(fp1);
    fclose(fp2);
}

int main(int argc, char *argv[])
{
    if(argc != 3)
        printf("Usage: copy src_file dest_file\n");
    else
        copy(argv[1], argv[2]);

    return 0;
}

//fgets.c
//练习使用fgets、gets、getchar、getc函数


#include <stdio.h>

int main(int argc, const char *argv[])
{
    char str[128] = {0};
    char ch;
    int i = 0;

    printf("fgets:");
    fgets(str, sizeof(str), stdin);
    printf("str=%s\n", str);

    printf("gets:");
    gets(str);
    printf("str=%s\n",str);

    printf("getchar:");
    while((ch = getchar()) != '\n')
        str[i++] = ch;
    printf("str=%s\n", str);

    i = 0;
    printf("getc:");
    while((ch = getc(stdin)) != '\n')
        str[i++] = ch;
    printf("str=%s\n", str);
    return 0;
}

//fgets_fputs_cp.c
//用fgets函数，实现copy函数的功能

#include <stdio.h>

void copy(char *src, char *dest)
{
    FILE *fp1, *fp2;
    char buff[1024];

    fp1 = fopen(src, "r");
    fp2 = fopen(dest, "w");

    if((fp1 == NULL) || (fp2 == NULL))
        printf("%s/%s open failure\n", src, dest);

    while((fgets(buff, sizeof(buff), fp1)) != NULL)
        fputs(buff, fp2);
    fclose(fp1);
    fclose(fp2);
}

int main(int argc, char *argv[])
{
    if(argc != 3)
        printf("Usage: copy src_file dest_file\n");
    else
        copy(argv[1], argv[2]);
    return 0;
}

//fprintf.c

//stdout是行缓冲，stderr是无缓冲
#include <stdio.h>

int main(int argc, const char *argv[])
{
    //int val = fprintf(stderr,"%s\n", "hello");
    //printf("val = %d\n", val);
    printf("%s", "1234");
    fflush(stdout);

    return 0;
}

//fscanf.c

//fscanf与scanf的区别
//        scanf是从stdin中读数据
//        fscanf是从文件指针指向的文件中读数据(包括stdin)

#include <stdio.h>

int main(int argc, const char *argv[])
{
    int m, n;

    fscanf(stdin, "%d %d", &m, &n);
    printf("m = %d n= %d\n", m, n);
    return 0;
}

//sprintf.c

//将format格式的变参列表，写入到指定字符串中

#include <stdio.h>

int main(int argc, const char *argv[])
{
    char buff[1024];
    //sprintf(buff, "%s\n", "abc");
    //printf("%s\n", buff);


    int val = 100;
    double d = 100.0;
    char *s = "abc";
    sprintf(buff, "%d%s%.1f", val, s, d);

    printf("buff = %s\n", buff);
    return 0;
}

//sscanf.c

//sscanf从指定字符串中读数据

#include <stdio.h>

int main(int argc, const char *argv[])
{
    int  m, n;
    char p[24] = {0};
    char *s = "123 abc 45";
    sscanf(s, "%d%s%d", &m, p, &n);
    printf("m = %d p = %s n = %n\n", m, p, n);
    return 0;
}

//my_scanf.c
#include <stdio.h>

void my_scanf(int *num)
{
    char buff[8] = {0};
    int i = 0;
    char ch;

    while((ch = getchar()) != '\n' && i < 8)
    {
        buff[i++] = ch;
    }

   *num = atoi(buff);
}

int main(int argc, const char *argv[])
{
    int num;

    my_scanf(&num);

    printf("num = %d\n", num);
    return 0;
}

//fread_fwrite_cp.c

//使用fread和fwrite函数，实现copy函数功能
//fread：读取指定块
//fwrite：写指定块

#include <stdio.h>
#include <stdint.h>

void copy(char *src, char *dest)
{
    FILE *srcp, *destp;
    size_t n;
    uint8_t arr[16];

    srcp = fopen(src, "rb");
    destp = fopen(dest, "wb");
    if((srcp == NULL) || (destp == NULL))
        printf("open file failure\n");

    while((n = fread(arr, sizeof(uint8_t), 16,srcp)) != 0)
        fwrite(arr, sizeof(uint8_t), n, destp);

    fclose(srcp);
    fclose(destp);

}

int main(int argc, char *argv[])
{
    if(argc == 3)
        copy(argv[1], argv[2]);
    else
        printf("Usage：copy src_file dest_file\n");
    return 0;
}

//fseek_ftell_rewind.c

//使用fseek、ftell、rewind函数，求一个文件的长度

#include <stdio.h>

int main(int argc, const char *argv[])
{
    FILE *fp;
    char ch;

    fp = fopen(argv[1], "r");
    if(fp == NULL)
        printf("open failure\n");

    fseek(fp, 0, SEEK_END);
    printf("%s: size= %ld\n", argv[1], ftell(fp));

    fclose(fp);
    return 0;
}

//2_file_append.c

//用fgets函数，实现将两个文件追加到第三个文件中

#include <stdio.h>

void append(char *src, char *dest, char *result)
{
    FILE *srcp, *destp, *resultp;
    char buff[1024];

    srcp = fopen(src, "r");
    destp = fopen(dest, "r");
    resultp = fopen(result, "a+");

    if((srcp == NULL) || (destp == NULL) || (result == NULL))
        printf("open file failure!\n");

    while((fgets(buff, sizeof(buff), srcp)) != NULL)
        fputs(buff, resultp);
    while((fgets(buff, sizeof(buff), destp)) != NULL)
        fputs(buff, resultp);
    fclose(srcp);
    fclose(destp);
    fclose(resultp);
}

int main(int argc, char *argv[])
{
    if(argc != 4)
        printf("Usage: append src dest result\n");
    else
        append(argv[1], argv[2], argv[3]);
    return 0;
}

//files_append.c

//实现将argv[1]~argv[n-2]所指的文件，追加到argv[n-1]所指文件中

#include <stdio.h>

void append(int argc, char *argv[])
{
    FILE *resultp, *srcp;
    char buff[1024];
    int i;

    resultp = fopen(argv[argc-1], "a");
    for (i = 1 ; i < argc - 1; i++)
    {
        srcp = fopen(argv[i], "r");
        if(srcp == NULL)
            printf("open file  %s failure\n", argv[i]);
        while((fgets(buff, sizeof(buff), srcp)) != NULL)
            fputs(buff, resultp);
        fclose(srcp);
    }

    fclose(resultp);

}

int main(int argc, char *argv[])
{
    append(argc, argv);
    return 0;
}