```
1、四舍五入：要保留的小数点位后面的以为如>=5，则向前进1，反之，舍去
//1️⃣
float testNumber1 = 4.83;
int result = （int）roundf(testNumber);
NSLog(@"roundf(%0.2f) = %d",testNumber,result);
//输出roundf(4.83) = 5;
//2️⃣
float testNumber1 = 4.23;
int result = （int）roundf(testNumber);
NSLog(@"roundf(%0.2f) = %d",testNumber,result);
//输出roundf(4.23) = 4;
```
```
2.进一：要保留的小数位后面一位无论为多少，都向前进1
//1️⃣
float testNumber1 = 4.83;
int result = （int）ceilf(testNumber);
NSLog(@"roundf(%0.2f) = %d",testNumber,result);
//输出roundf(4.83) = 5;
//2️⃣
float testNumber1 = 4.23;
int result = （int）ceilf(testNumber);
NSLog(@"ceilf(%0.2f) = %d",testNumber,result);
//输出rceilf(4.23) = 5;
```
```
3.退位：要保留的小数位后面一位无论为多少，都舍去
//1️⃣
float testNumber1 = 4.83;
int result = （int）floorf(testNumber);
NSLog(@"floorf(%0.2f) = %d",testNumber,result);
//输出floorf(4.83) = 4;
//2️⃣
float testNumber1 = 4.23;
int result = （int）floorf(testNumber);
NSLog(@"floorf(%0.2f) = %d",testNumber,result);
//输出floorf(4.23) = 5;
```
