（20200501）【C/C++】txt文件数据读取之fgets和fscanf

参考：

【1】https://blog.csdn.net/daiyutage/article/details/8540932?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromBaidu-1&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromBaidu-1

【2】https://mp.csdn.net/console/editor/html/105208262

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#define _CRT_SECURE_NO_WARNINGS
#include 
#include 
#include 
using namespace std;

//C语言向文件存入数据
void writeFile()
{
	FILE *fp;
	fp = fopen("0501.txt", "w");
	if (!fp)
	{
		printf("文件打开失败\n");
		return;
	}

	fprintf(fp, "%s\n", "1234hello");
	fprintf(fp, "%s\n", "1234hello");
	fprintf(fp, "%s\n", "1234 hello");
	fprintf(fp, "%s\n", "12.34 hello");

	fclose(fp);
	printf("数据存储完成\n");
}

//使用C语言读取文件
void ReadFile1()
{
	FILE *fp;
	fp = fopen("0501.txt", "r");
	if (!fp)
	{
		printf("文件打开失败\n");
		return;
	}

	//读取第一行:fgets
	char str1[20];
	fgets(str1, 10, fp);
	cout << str1 << endl;
	//分解第一行
	//char str1_1[20] = { 0 };   //初始化为空
	char str1_1[20];
	memset(str1_1, '\0', sizeof(char)* 20); //初始化为空
	strncpy(str1_1, str1, 4);
	cout << str1_1 << endl;
	char str1_2[20] = { 0 };
	strncpy(str1_2, str1 + 4, 5);
	cout << str1_2 << endl;

	//读取第2行:fscanf
	char str2[20];
	fscanf(fp, "%s", str2);
	cout << str2 << endl;
	char str2_1[20] = { 0 };
	strncpy(str2_1, str2, 4);
	cout << str2_1 << endl;
	char str2_2[20] = { 0 };
	strncpy(str2_2, str2 + 4, 5);
	cout << str2_2 << endl;

	//读取第三行:fscanf
	int str3_1;
	char str3_2[20];
	fscanf(fp, "%d %s", &str3_1, str3_2);
	printf("%d %s\n", str3_1, str3_2);

	//读取第4行:fscanf
	float str4_1;
	char str4_2[20];
	fscanf(fp, "%f %s", &str4_1, str3_2);
	printf("%f %s\n", str4_1, str3_2);

	fclose(fp);
	printf("数据读取完成\n");
}



int main()

{
	writeFile();//使用C语言写文件
	ReadFile1();//使用C语言读取文件

	return 0;
}

 

%===20200508 补充===

1】

2】

方式1：

#include 
#include 
#include 

int main(void)
{
	FILE *fp;
	fp = fopen("0501.txt", "r");

	char ch1;
	//char ch2[10];
	while (!feof(fp))
	{
		ch1 = fgetc(fp);
		printf("%c", ch1);
		//strcpy(ch2 , fgets(ch2,10,fp));
	}

	fclose(fp);

	system("pause");
	return 0;

}

方式2：

#include 
#include 
#include 

int main(void)
{
	FILE *fp;
	fp = fopen("0501.txt", "r");

	char ch1;
	while (!feof(fp))
	{
		ch1 = fgetc(fp);
		if (ch1 == EOF)
		{
			break;
		}
		printf("%c", ch1);

	}
	fclose(fp);
	system("pause");
	return 0;

}

方式3：

#include 
#include 
#include 

int main(void)
{
	FILE *fp;
	fp = fopen("0501.txt", "r");

	char ch1;
	while ((ch1=fgetc(fp))!= EOF)
	{
		printf("%c", ch1);

	}
	fclose(fp);
	system("pause");
	return 0;

}