C语言操作文件

Source Code

C语言简单实例

请大家阅读.

/* 本程序展示C语言操作文件的基本方法。
The latest C standard C11 provides a new mode “x” which is exclusive create-and-open mode.
Mode “x” can be used with any “w” specifier, like “wx”, “wbx”.
When x is used with w, fopen() returns NULL if file already exists or could not open.
*/
#include <stdio.h>
#include <stdlib.h>
int main()
{
    FILE *fp = fopen("test.txt", "wx");
    if (fp == NULL)
    {
        puts("Couldn't open file or file already exists");
        //exit(0);
    }
    else
    {
        fputs("This is a test for FILEs operation.", fp);
        puts("Write done.");
        fclose(fp);
    }
    // Open file
    fp = fopen("test.txt", "r");
    if (fp == NULL)
    {
        printf("Cannot open file. \n");
        exit(0);
    }
    // Read contents from file
    char c = fgetc(fp);
    while (c != EOF)
    {
        printf ("%c", c);
        c = fgetc(fp);
    }
    printf("\n");
    fclose(fp);
    return 0;
}