#include <stdio.h>
#include <math.h>
void metersToFeetAndInches(double meters,unsigned int *ftPtr,double *inPtr){
//这个函数假定meters的值是非负数
//将meters变量的值转化为feet的值，类型为浮点数
double rawFeet = meters * 3.281; //e.g. 2.4536
printf("rawFeet: %lf ", rawFeet);
//计算类型为无符号的整形的feet变量的值
unsigned int feet = (unsigned int)floor(rawFeet);
printf("ftPtr: %p ", ftPtr);
printf("*ftPtr: %d ", *ftPtr);
//将feet变量的值存储在提供的地址里
//先检查指针是否为NULL
if(ftPtr){
printf("------------------------------------------ ");
printf("Storing %u to the address %p ",feet ,ftPtr);
*ftPtr = feet;
printf("ftPtr: %p ", ftPtr);
printf("*ftPtr: %d ", *ftPtr);
}
//计算英寸
double fractionalFoot = rawFeet - feet;
double inches = fractionalFoot * 12.0;
printf("fractionalFoot: %lf ", fractionalFoot);
printf("inches: %lf ", inches);
printf("------------------------------------------ ");
//将inches变量的值保存到传入的地址
//先检查指针是否为NULL
if(inPtr){
printf("Storing %.2f to the address %p ", inches, inPtr);
*inPtr = inches;
printf("inPtr: %p ", inPtr);
printf("*inPtr: %lf ", *inPtr);
}
}
int main(int argc, const char * argv[]) {
double meters = 3.0;
unsigned int feet;
double inches;
metersToFeetAndInches(meters, &feet, &inches);
printf("%.1f meters is equal to %d feet and %.1f inches.",meters,feet,inches);
return 0;
}
结果：
rawFeet: 9.843000
ftPtr: 0x7ffeefbff514
*ftPtr: 0
------------------------------------------
Storing 9 to the address 0x7ffeefbff514
ftPtr: 0x7ffeefbff514
*ftPtr: 9
fractionalFoot: 0.843000
inches: 10.116000
------------------------------------------
Storing 10.12 to the address 0x7ffeefbff508
inPtr: 0x7ffeefbff508
*inPtr: 10.116000
3.0 meters is equal to 9 feet and 10.1 inches.Program ended with exit code: 0