在 do while 循環中省略了 scanf

Question

我有這個程序，在它的第一個循環中它按預期工作，但是從第二個循環開始，它不執行第一個 scanf。 我們沒有教過指針，所以我不知道他們是否能解決問題。 我應該用另一種循環語法來解決這個問題嗎？ 任何幫助表示贊賞。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[])
{
    char type[20];
    int amount;
    double price;
    double priceP;
    double priceG;
    double priceA;
    double pricePL;
    double priceC;
    price=0;
    char frouro[4]= "add";
    char payment[5];
    double refund;

    do{

       printf("What kind of material do you want to recycle today?. It has to be either paper , glass, aluminium, plastic or cloth\n");

       scanf(" %s" , &type);

       printf("how many materials do you want to recycle today? It has to be more than 1 and a maximum of 10\n");

       scanf(" %d" , &amount);

       if (strcmp(type, "paper") == 0)
          { 

           priceP = priceP + amount * 0.10;

          }   
       if (strcmp(type, "glass") == 0)
          { 

           priceG =priceP + amount * 0.20;

          }
       if (strcmp(type, "aluminium") == 0)
          { 

          priceA =  priceA + amount * 0.15;

          }
       if (strcmp(type, "plastic") == 0)
          { 

          pricePL =  pricePL +amount * 0.05;

          }  
       if (strcmp(type, "cloth") == 0)
          {

           priceC =  priceC + amount * 0.50;

          }  
      printf("do you want to do anything else?\n");

      scanf(" %c", &frouro);
      }while(strcmp(frouro,"add")==0 && strcmp(frouro,"end")!=0);

      return 0;
}

Answer 1

更改scanf(" %c", &frouro); 到scanf("%s", &frouro); .

當你在過程中存儲1個字符， while條件檢查這將是始終為false。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[])
{
    char type[20];
    int amount;
    double price;
    double priceP;
    double priceG;
    double priceA;
    double pricePL;
    double priceC;
    price=0;
    char frouro[4]= "add";
    char payment[5];
    double refund;

    do{

       printf("What kind of material do you want to recycle today?. It has to be either paper , glass, aluminium, plastic or cloth\n");

       scanf(" %s" , &type);

       printf("how many materials do you want to recycle today? It has to be more than 1 and a maximum of 10\n");

       scanf(" %d" , &amount);

       if (strcmp(type, "paper") == 0)
          { 

           priceP = priceP + amount * 0.10;

          }   
       if (strcmp(type, "glass") == 0)
          { 

           priceG =priceP + amount * 0.20;

          }
       if (strcmp(type, "aluminium") == 0)
          { 

          priceA =  priceA + amount * 0.15;

          }
       if (strcmp(type, "plastic") == 0)
          { 

          pricePL =  pricePL +amount * 0.05;

          }  
       if (strcmp(type, "cloth") == 0)
          {

           priceC =  priceC + amount * 0.50;

          }  
      printf("do you want to do anything else?\n");

      scanf("%s", &frouro);
      }while(strcmp(frouro,"add")==0 && strcmp(frouro,"end")!=0);

      return 0;
}