[長知識] C語言 - 玩玩 參數傳值和傳址

#include 
#include 
 
 //傳址，希望函數幫我改值的狀況就用傳址! 
int dayBetweenByAddress(int *in, int *out){
 int temp;
 if(in >out){
  temp = *in;
  *in = *out;
  *out = temp; 
 } 
 return *out-*in;
}

//傳值 
int dayBetweenByValue(int in, int out){
 int temp;
 if(in >out){
  temp = in;
  in = out;
  out = temp; 
 } 
 return out-in;
}


int main(){
 
 int day1, day2, dayByAddress, dayByValue;
 
 day1 = 10;
 day2 = 7;

 dayByAddress = dayBetweenByAddress(&day1, &day2);
 dayByValue = dayBetweenByValue(day1, day2);
 
 printf("-----Call by value-----\n");
 printf("%d月到 %d月，共 %d個月\n", day1, day2, dayByValue);
 printf("-----Call by address---\n");
 printf("%d月到 %d月，共 %d個月\n", day1, day2, dayByAddress);
 
}

輸出結果: