NSString转C语言翻转字符串

#pragma mark - C语言实现翻转字符串笔记
- (void)recorverStringNote{

//翻转字符串
NSString *abc = @"abcsssssssssssssssssssssssssssssssssssssssss";
const char *a = [abc UTF8String];
unsigned long int end = strlen(a) - 1;

char *b = malloc(sizeof(char)*(end+2));
for(int i = 0; i<=end; i++){
b[end-i] = a[i];
}
b[end+1] = '\0';
abc = [NSString stringWithCString:b encoding:NSUTF8StringEncoding];
NSLog(@"%@",abc);
free(b);
}