C语言及程序设计初步例程-42 将数据输出到文本文件

贺老师教学链接  C语言及程序设计初步 本课讲解

文件的操作步骤

#include <stdio.h>
#include <stdlib.h>
int main()
{
    FILE *fp;
    int i, d;

    fp=fopen("data.txt","w");
    if(fp==NULL)
    {
        printf("File cannot open! " );
        exit(0);
    }

    for(i=0; i<10; i++)
    {
        scanf("%d", &d);
        fprintf(fp,"%d\t", d);
    }

    fclose(fp);
    return 0;
}

实用写文件方式之——格式化输出

#include <stdio.h>
#include <stdlib.h>
int main()
{
    FILE *fp;
    int i, No;
    float salary;
    fp=fopen("data.csv","w");
    if(fp==NULL)
    {
        printf("File cannot open! " );
        exit(0);
    }
    //输入5名员工的工号，并保存到文件中
    for(i=0; i<5; i++)
    {
        scanf("%d %f", &No, &salary);
        fprintf(fp,"%d, %.2f\n", No, salary);
    }
    fclose(fp);
    return 0;
}

实用读文件方式之——格式化输入

#include <stdio.h>
#include <stdlib.h>
int main()
{
    FILE *fp;
    int i, No;
    float salary;
    fp=fopen("data.csv","r");
    if(fp==NULL)
    {
        printf("File cannot open! " );
        exit(0);
    }
    //输入5名员工的工号，并保存到文件中
    for(i=0; i<5; i++)
    {
        fscanf(fp, "%d,%f", &No, &salary);
        printf("%d\t%.2f\n", No, salary);
    }
    fclose(fp);
    return 0;
}

实用写文件方式之——将字符写入文件

#include <stdio.h>
#include <stdlib.h>
int main()
{
    FILE *fp;
    char c;
    if ((fp=fopen( "data.dat" , "w" ))==NULL)
    {
        printf("File cannot open!");
        exit(0);
    }
    while((c=getchar())!=EOF )
        fputc(c,fp );
    fclose(fp);
    return 0;
}

实用读文件方式之——从文件中读取字符

#include <stdio.h>
#include <stdlib.h>
int main()
{
    FILE *fp;
    char c;
    if ((fp=fopen( "data.dat" , "r" ))==NULL)
    {
        printf("File cannot open!");
        exit(0);
    }
    while((c=fgetc(fp))!=EOF)
        putchar(c);
    fclose(fp);
    return 0;
}