#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main()
{
FILE* fp;
errno_t err;
char str[100];
int i = 0;
if ((err = fopen_s(&fp,"test", "w")) == NULL)
{
printf("cannot open file\n");
exit(0);
}
printf("input a string:\n");
gets_s(str);
while (str[i] != '!')
{
if (str[i] >= 'a' && str[i] <= 'z')
str[i] -= 32;
i++;
}
fputs(str, fp);
fclose(fp);
err = fopen_s(&fp,"test", "r");
fgets(str, strlen(str) + 1, fp);
printf("%s\n", str);
fclose(fp);
return 0;
}
这个我点完开始运行咋跳出的是“cannot open file”啊,求解