c语言文件操作

一 概述

FILE* fp;

w:  写入模式

a:  插入模式

fp = fopen("t3.txt","a");

fputs("test1",fp);

fprintf(fp,"t6 test%d\n",d);

二 举例

1 文件写入

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(){
    FILE* fp;
    fp = fopen("t3.txt","w");
    if(fp!=NULL){
        fputs("test1",fp);
        fputs("test2",fp);
    }
    fclose(fp);
}

2 文件追加

 

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(){
    FILE* fp;
    fp = fopen("t3.txt","a");
    if(fp!=NULL){
        fputs("test1\n",fp);
        fputs("test2\n",fp);
    }
    fclose(fp);
}

3 绝对路径

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(){
    FILE* fp;
    fp = fopen("/home/xjc/ccode/logtest/t3.txt","a");
    if(fp!=NULL){
        fputs("test5\n",fp);
        fputs("test6\n",fp);
    }
    fclose(fp);
}

4 格式化输入

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(){
    FILE* fp;
    fp = fopen("/home/xjc/ccode/logtest/t3.txt","a");
    if(fp!=NULL){
        int d = 6;
        fprintf(fp,"t6 test%d\n",d);
    }
    fclose(fp);
}