ios中处理四舍五入的问题

处理四舍五入主要使用下面这个方法:

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-(NSString *)notRounding:(float)price afterPoint:(int)position{
    NSDecimalNumberHandler* roundingBehavior = [NSDecimalNumberHandler decimalNumberHandlerWithRoundingMode:NSRoundDown scale:position raiseOnExactness:NO raiseOnOverflow:NO raiseOnUnderflow:NO raiseOnDivideByZero:NO];
    NSDecimalNumber *ouncesDecimal;
    NSDecimalNumber *roundedOunces;
    
    ouncesDecimal = [[NSDecimalNumber alloc] initWithFloat:price];
    roundedOunces = [ouncesDecimal decimalNumberByRoundingAccordingToBehavior:roundingBehavior];
    [ouncesDecimal release];
    return [NSString stringWithFormat:@"%@",roundedOunces];
}

介绍一下参数:
price:需要处理的数字,
position:保留小数点第几位,
然后调用

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float s =0.126;
    NSString *sb = [self notRounding:s afterPoint:2];
    NSLog(@"sb = %@",sb);
输出结果为:sb = 0.12

接下来介绍NSDecimalNumberHandler初始化时的关键参数:decimalNumberHandlerWithRoundingMode:NSRoundDown,
NSRoundDown代表的就是 只舍不入。
scale的参数position代表保留小数点后几位。