char a[80]={'\0'};
scanf_s("%s\n,a,sizof(a)); 改为 gets(a);
把
a[i]='\0'
改为
b[i]='\0';
把scanf_s中%s后面的\n去掉,输入时不要指定回车符
另外最后应该是b[i] = 0,不是a[i] = 0
最后打印应该是printf("%s\n",b);
#include <stdio.h>
int main()
{
char a[80] = {0};
char b[80] = {0};
printf("输入字符串:");
scanf_s("%s",a,sizeof(a));
int i;
for(i=0;a[i] != 0;i++)
{
b[i] = a[i];
if(b[i] >= 'a' && b[i] <= 'z')
b[i] -= 32;
}
printf("%s\n",b);
return 0;
}