C语言训练-大、小写问题 为什么不能 gets(a); strlwr(a);这样写？

解题思路:

注意事项:

参考代码:

                                                                #include<stdio.h>

                                                                #include<string.h>

                                                                int main()

                                                                {

                                                                         char a[100];

                                                                         int i=0;

                                                                         gets(a);

                                                                         //strlwr(a);

                                                                         while(a[i]!='\0'){

                                                                                 if(a[i]>='A' && a[i]<='Z')

                                                                                         a[i]=a[i]+32;

                                                                                 i++;

                                                                         }

                                                                         puts(a);

                                                                         return 0;

                                                                }