C語言練習-文件的操作

1.由鍵盤到文件

void to_file()
{
    FILE *fp ;
    char ch,fname[10];
    printf("文件名:"); // 把txt格式也當名字輸進去
    gets(fname);
    if ((fp=fopen(fname,"w"))==NULL)
    {
        printf("cannot open\n");
        exit(0);
    }
    while ((ch=getchar())!='#')
        fputc(ch,fp);
     fclose(fp);

}

2.從一個文件拷貝到另一個文件并顯示在屏幕上

void copy_and_show()
{
    FILE *fp1,*fp2;
    char ch;
    fp1=fopen("test1.txt","r");
    fp2=fopen("test2.txt","w");
    while (!feof(fp1))
    {
        ch=fgetc(fp1);
        putchar(ch);
        fputc(ch,fp2);
    }
    fclose(fp1);
    fclose(fp2) ;
}

3.自建文件并計算其中字母，數字和空格的個數

void count_in_file()
{
    FILE *fp;
    int cnt=0;
    char ch,name[20];
    printf("Enter the name: \n");
    gets(name);
    if((fp=fopen(name,"w"))==NULL)
    {
        printf("Cannot open\n");
        exit(0);
    }
    while((ch=getchar())!='#')
        fputc(ch,fp);
    fclose(fp);
    if((fp=fopen(name,"r"))==NULL)
    {
        printf("Cannot open\n");
        exit(0);
    }
    while(!feof(fp))
    {
        ch=fgetc(fp);
        if((ch==' ')||(ch>='0'&&ch<='9')||(ch>='A'&&ch<='Z')||(ch>='a'&&ch<='z'))
            cnt++;
    }
    printf("%d",cnt);
    fclose(fp);
}