函数A将字符串str1转成小写

#include <stdio.h> 
#include <stdlib.h> 
char* str1   = "ABDFLjlero我们都是saf";
char*  ToLower(char s[]) 
{ 
static size_t i=sizeof(s);      
for (i; i>=0; i--) { 
if (s[i]>"A" && s[i]<"Z") { 
s[i] += 32; 
} 
} 
return s;
int A() 
{ 
printf("old str[%s] after lower[%s]n", str1, ToLower(str1)); 
}