IOS 四舍五入 进一法 去尾法

float numberToRound;

   int result;

    numberToRound = 4.51;

    result = (int)roundf(numberToRound);

    NSLog(@"roundf(%f) = %d", numberToRound, result); // roundf(4.510000) = 5

    result = (int)ceilf(numberToRound);

    NSLog(@"ceilf(%f) = %d", numberToRound, result); // ceilf(4.510000) = 5

    result = (int)floorf(numberToRound);

    NSLog(@"floorf(%f) = %d", numberToRound, result); // floorf(4.510000) = 4

    numberToRound = 10.49;

    result = (int)roundf(numberToRound);

    NSLog(@"roundf(%f) = %d", numberToRound, result); // roundf(10.490000) = 10

    result = (int)ceilf(numberToRound);

    NSLog(@"ceilf(%f) = %d", numberToRound, result); // ceilf(10.490000) = 11

    result = (int)floorf(numberToRound);

    NSLog(@"floorf(%f) = %d", numberToRound, result); // floorf(10.490000) = 10

    numberToRound = -2.49;

    result = (int)roundf(numberToRound);

    NSLog(@"roundf(%f) = %d", numberToRound, result); // roundf(-2.490000) = -2

    result = (int)ceilf(numberToRound);

    NSLog(@"ceilf(%f) = %d", numberToRound, result); // ceilf(-2.490000) = -2

    result = (int)floorf(numberToRound);

    NSLog(@"floorf(%f) = %d", numberToRound, result); // floorf(-2.490000) = -3

    numberToRound = -3.51;

    result = (int)roundf(numberToRound);

    NSLog(@"roundf(%f) = %d", numberToRound, result); // roundf(-3.510000) = -4

    result = (int)ceilf(numberToRound);

    NSLog(@"ceilf(%f) = %d", numberToRound, result); // ceilf(-3.510000) = -3

    result = (int)floorf(numberToRound);

    NSLog(@"floorf(%f) = %d", numberToRound, result); // floorf(-3.510000) = -4

IOS 四舍五入 进一法 去尾法

原文：http://www.cnblogs.com/yujidewu/p/5724966.html