object-c中NSString与int和float的相互转换

NSString *tempA = @"123";

NSString *tempB = @"456";

1，字符串拼接

NSString *newString = [NSString stringWithFormat:@"%@%@",tempA,tempB];

2，字符转int

int intString = [newString intValue];

3，int转字符

NSString *stringInt = [NSString stringWithFormat:@"%d",intString];

4，字符转float

float floatString = [newString floatValue];

5，float转字符

NSString *stringFloat = [NSString stringWithFormat:@"%f",intString];

四舍五入问题

-(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

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。