ios 给数字每隔三位加一个，号

//金钱每三位加一个逗号，经过封装的一个方法直接调用即可，传一个你需要加，号的字符串就好了
+(NSString *)countNumAndChangeformat:(NSString *)num
{
    if([num rangeOfString:@"."].location !=NSNotFound) //这个判断是判断有没有小数点如果有小数点，需特别处理，经过处理再拼接起来
     {
        NSString *losttotal = [NSString stringWithFormat:@"%.2f",[num floatValue]];//小数点后只保留两位
        NSArray *array = [losttotal componentsSeparatedByString:@"."];
        //小数点前:array[0]
        //小数点后:array[1]
        int count = 0;
        num = array[0];
        long long int a = num.longLongValue;
        while (a != 0)
        {
            count++;
            a /= 10;
        }
        NSMutableString *string = [NSMutableString stringWithString:num];
        NSMutableString *newstring = [NSMutableString string];
        while (count > 3) {
            count -= 3;
            NSRange rang = NSMakeRange(string.length - 3, 3);
            NSString *str = [string substringWithRange:rang];
            [newstring insertString:str atIndex:0];
            [newstring insertString:@"," atIndex:0];
            [string deleteCharactersInRange:rang];
        }
        [newstring insertString:string atIndex:0];
        NSMutableString *newString = [NSMutableString string];
        newString =[NSMutableString stringWithFormat:@"%@.%@",newstring,array[1]];
        return newString;
    }else {
        int count = 0;
        long long int a = num.longLongValue;
        while (a != 0)
        {
            count++;
            a /= 10;
        }
        NSMutableString *string = [NSMutableString stringWithString:num];
        NSMutableString *newstring = [NSMutableString string];
        while (count > 3) {
            count -= 3;
            NSRange rang = NSMakeRange(string.length - 3, 3);
            NSString *str = [string substringWithRange:rang];
            [newstring insertString:str atIndex:0];
            [newstring insertString:@"," atIndex:0];
            [string deleteCharactersInRange:rang];
        }
        [newstring insertString:string atIndex:0];
        return newstring;
    }
}