211 sscanf_s 和 fgets (从buffer里读取file_stream)

1 从buffer里读取file_stream中带标签的数据

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
int main(void) {
	FILE* file_stream = NULL;
	errno_t err = fopen_s(&file_stream, "E:\\桌面\\cs.txt", "r");
	if (err != 0 || file_stream == NULL) {
		perror("file opening failed");
		return EXIT_FAILURE;
	}
	char line[200];
	char name[100] = "";
	int age = 0;
	char gender = 'N';
	float num = 0.00f;
	 while(fgets(line, sizeof(line), file_stream) != NULL)
	{
		if (strstr(line, "name:") != NULL) {
		
			sscanf_s(line, "name:%s", name, (unsigned)_countof(name));
		
		}
		if (strstr(line, "age:") != NULL) {
		
			sscanf_s(line, "age:%d", &age);
		}
		if (strstr(line, "gender:") != NULL) {
		
			sscanf_s(line, "gender:%c", &gender, 1);
		}
		if (strstr(line, "num") != NULL) {
		
			sscanf_s(line, "num:%f", &num);
		}
	}
	printf("name:%s\n", name);
	printf("age:%d\n", age);
	printf("gender:%c\n", gender);
	printf("num:%.4f\n", num);
	fclose(file_stream);
	return 0;
}

2 output：

name:Lily
age:23
gender:G
num:3.1456

3file

4 注意点：

1.sscanf_s中参数的顺序,第二个参数是格式化字符串（char* format）
2.sscanf_s 不支持指定浮点数的小数位数,只需要用 %f 即可