曾有需求做个用户名中非法字符的判断，要求是只能输入中英文和数字，其他字符一律非法，故写了下边一个程序mark一下吧~~

NSString *testString = @"春1mianBU觉晓";

NSString *perchar;

    int alength = [testString length];

    for (int i = 0; i<alength; i++) {

        char commitChar = [testString characterAtIndex:i];

        NSString *temp = [testString substringWithRange:NSMakeRange(i,1)];

        const char *u8Temp = [temp UTF8String];

        if (3==strlen(u8Temp)){

            NSLog(@"字符串中含有中文");

        }else if((commitChar>64)&&(commitChar<91)){

    NSLog(@"字符串中含有大写英文字母");

        }else if((commitChar>96)&&(commitChar<123)){

            NSLog(@"字符串中含有小写英文字母");

        }else if((commitChar>47)&&(commitChar<58)){

            NSLog(@"字符串中含有数字");

        }else{

    NSLog(@"字符串中含有非法字符");

}

    }