c - 如何让程序在询问 y 或 n 时重复

Question

我试图让这个程序在提示 Y 或 N 时重复，但由于某种原因我似乎无法让它正常工作，这是我剩下的最后一件事，我很确定代码的其余部分是正确的我认为我需要的是如果用户输入“Y”则重复整个程序，或者如果用户输入“N”则退出

 int main(void)
 {
 // Constant and Variable Declarations
 const int MPH_SPEED_MIN = 1;
 const int MPH_SPEED_MAX = 100;
 const int HOURS_TRAVLED_MIN = 1;
 int mphSpeed = 1;
 int hoursEntered = 0;
 int distanceTraveled = 0;
 int counterNum = 0;
 int distanceNum = 0;
 char ch = 'y';



  // *** Input ***
  do {
    printf("What is the speed of the vehicle in MPH? ");
    scanf("%d", &mphSpeed);
    while ((mphSpeed < MPH_SPEED_MIN) || (mphSpeed > MPH_SPEED_MAX)) {
    printf("\tThe speed entered must be between %d and %d inclusive 
    \n",MPH_SPEED_MIN, MPH_SPEED_MAX);
        printf("\tPlease re-enter the speed of the vehicle in MPH: ");
        scanf("%d", &mphSpeed);
    }

    printf("How many hours has it traveled? ");
    scanf("%d", &hoursEntered);

    while (hoursEntered < HOURS_TRAVLED_MIN) {
        printf("\tThe hours traveled must be a positive number.\n");
        printf("\tPlease re-enter the number of hours traveled: ");
        scanf("%d", &hoursEntered);
    }
    printf("\n");
    printf("Hour\tDistance Traveled\n");
    distanceTraveled = hoursEntered * mphSpeed;
    for (counterNum = 1; counterNum <= hoursEntered; counterNum++) {
        distanceNum = distanceTraveled * counterNum;
        printf("%d\t%d miles\n", counterNum, distanceNum);
    }
    printf("\n");
    printf("Run the program again (Y/N)? ");
    scanf("%c", &ch);
    printf("\n");
} while (ch == 'Y' || ch == 'y');


; return 0;

Answer 1

当使用 scanf(%c... 读入时，该语句很可能会从先前的输入中读入缓冲区中留下的新行字符。而是读入字符串，因为 %s 忽略任何前导空格(包括缓冲区中留下的换行符)。

尝试...

  char exitYN[2];
  if (scanf("%1s",exitYN) != 1) {
     exitYN[0]='N';
  }
  char ch = exitYN[0];
} while (ch == 'Y' || ch == 'y');