c++freopen函數

C語言中的freopen()函數 (freopen() function in C)

Prototype:

原型：

    FILE* freopen(const char *str, const char *mode, FILE *stream);

Parameters:

參數：

    const char *str, const char *mode, FILE *stream

Return type: FILE*

返回類型： FILE *

Use of function:

使用功能：

The prototype of the function freopen() is:

函數freopen()的原型為：

    FILE* freopen(const char *str, const char *mode, FILE *stream);

The freopen() function opens the existing stream into another file. The end-of-file and error flag is cleared in this process. The file named as str with its operation mode, opens it into the file stream named as stream. The freopen() function acts similar to the fopen() function. In the following output we can see the work of the function.

freopen()函數將現有流打開到另一個文件中。 文件結束和錯誤標志在此過程中被清除。 以其操作模式命名為str的文件將其打開到名為stream的文件流中 。 freopen()函數的作用類似于fopen()函數。 在以下輸出中，我們可以看到該函數的工作。

C中的freopen()示例 (freopen() example in C)

#include <stdio.h>
#include <stdlib.h>
int main(){
//Initialize the file pointer
FILE *f,*fp;
//Take a array of characters 
char ch[100];
//Create the file for write operation
f=fopen("includehelp.txt","w");
printf("Enter five strings\n");
for(int i=0;i<4;i++){
//take the strings from the users
scanf("%[^\n]",&ch);
//write back to the file
fputs(ch,f);
//every time take a new line for the new entry string 
//except for last entry.Otherwise print the last line twice
fputs("\n",f);
//clear the stdin stream buffer
//if we don't write this then after taking string 
fflush(stdin);
}
//%[^\n] is waiting for the '\n' or white space
//take the strings from the users
scanf("%[^\n]",&ch);
fputs(ch,f);
//reopen the file for read operation
fp=freopen("includehelp.txt","r",fp); 
printf("File content is--\n");
printf("\n...............print the strings..............\n\n");
while(!feof(fp)){
//takes the first 100 character in the character array 
fgets(ch,100,fp);
//and print the strings
printf("%s",ch);
}
//close the files
fclose(fp);
fclose(f);
return 0;
}

Output

輸出量

翻譯自: https://www.includehelp.com/c-programs/freopen-function-in-c-language-with-example.aspx

c++freopen函數