哪里错了？该怎么改？

[nabs0607]

#include <stdio.h>
#include <time.h>

int main() {
int i = 0, x, r, get = 0, lost = 0, number;
int t1 = 0, t2 = 0;
char option, go;

do {
i++;
srand(time(0));
x = rand() % 12 + 1;
printf("=======================================================\n");
printf("Guesses Choice:\n");
printf("O-Odd E-Even L-Low M-Medium H-High N-Number\n");
printf("=======================================================\n");
printf("Enter your choice: ");
scanf("%c", &option);
getchar();
printf("Point at risk: ");
scanf("%d", &r);

switch (option) {

case 'O':
case 'o':
printf("Odd number\n");
if( (x % 2) == 1) get = r;
else lost = r;
break;
case 'E':
case 'e':
printf("Even number\n");
if( (x % 2) == 0) get = r;
else lost = r;
break;
case 'L':
case 'l':
printf("Low number\n");
if(x <= 4) get = 2 * r;
else lost = r;
break;
case 'M':
case 'm':
printf("Medium number\n");
if(x >= 5 && x <= 8) get = 2 * r;
else lost = r;
break;
case 'H':
case 'h':
printf("High number\n");
if(x >= 9) get = 2 * r;
else lost = r;
break;
case 'N':
case 'n':
printf("A number\n");
printf("Enter your number: \n");
scanf("%d", &number);
if(x == number) get = 12 * r;
else lost = r;
break;
default:
printf("Try again!\n");
}

printf("The winning number is %d.\n", x);
if(get > 0) printf("You won %d points.\n", get);
else printf("You lost %d points.\n", lost);
t1 += get;
t2 += lost;
printf("Continue (Y/N)? ");
scanf("%c", &go);
getchar();
} while (go == 'Y' || go == 'y');
printf("Total number of guesses: %d\n", i);
printf("Your current point: %d\n", t1 - t2);
system("pause");
}

为何不能循环?
红色字体该放哪?

[visp]

少了一个#include <stdlib.h> 然后再所有要输入，但是可能输入错误的地方再输入后，加上清空输入缓冲区fflush(stdin)

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

int main() {
  int ret;
  int i = 0, x, r, get = 0, lost = 0, number;
  int t1 = 0, t2 = 0;
  char option, go;

  do {
  	//这里加一个 
  	fflush(stdin);
    i++;
    srand(time(0));
    x = rand() % 12 + 1;
    printf("=======================================================\n");
    printf("Guesses Choice:\n");
    printf("O-Odd E-Even L-Low M-Medium H-High N-Number\n");
    printf("=======================================================\n");
    printf("Enter your choice: ");
	scanf("%c", &option);
	
	//这里加一个
	fflush(stdin);	
	//getchar();

    printf("Point at risk: "); 
    ret = scanf("%d", &r);
    
    //如果输入的不是数字，就清除输入流缓冲 
    if (ret == 0)
    {
		fflush(stdin);
	}
    
    switch (option) {
           
      case 'O':
      case 'o':
        printf("Odd number\n");
        if( (x % 2) == 1) get = r;
          else lost = r;
        break;
      case 'E':
      case 'e':
        printf("Even number\n");
        if( (x % 2) == 0) get = r;
          else lost = r;
        break;
      case 'L':
      case 'l':
        printf("Low number\n");
        if(x <= 4) get = 2 * r;
          else lost = r;
        break;
      case 'M':
      case 'm':
        printf("Medium number\n");
        if(x >= 5 && x <= 8) get = 2 * r;
          else lost = r;
        break;
      case 'H':
      case 'h':
        printf("High number\n");
        if(x >= 9) get = 2 * r;
          else lost = r;
        break;
      case 'N':
      case 'n':
        printf("A number\n");
        printf("Enter your number: \n");
        scanf("%d", &number);
        if(x == number) get = 12 * r;
          else lost = r;
        break;
      default:
        printf("Try again!\n");
    }

    printf("The winning number is %d.\n", x);
    if(get > 0) printf("You won %d points.\n", get);
   	  else printf("You lost %d points.\n", lost);
   	t1 += get;
   	t2 += lost;
    printf("Continue (Y/N)? \n");
    //getchar();
    fflush(stdin);
	scanf("%c", &go);
    
  } while (go == 'Y' || go == 'y');
  printf("Total number of guesses: %d\n", i);
  printf("Your current point: %d\n", t1 - t2);
  system("pause");
}

[赵4老师]

在每个最后不带\n的printf后面加fflush(stdout); 在每个不想受接收缓冲区旧内容影响的scanf前面加rewind(stdin); 另外请检查scanf的返回值。

//请今后要用
int c;
scanf("%c",&c);
//时，都改为
char s[2];
int c;
scanf("%1s",s);
c=s[0];

[ReedLi]

scanf( "%c", &r); 只是读入一个字符,而你在输入时实际上输入的是:某个字符+Enter,Enter 产生的'\n' 也会停留在输入缓冲区中,下次调用 scanf( "%c", &number);或者scanf("%c", &go);时就会直接读到 ‘\n’ 而不是等待你再次输入! 因此，在scanf("%d", &r); 和 scanf("%d", &number); 后加getchar(); 即可。

[huoyun0]

按我的写就对了 #include <stdio.h> #include <time.h> int main() { int i = 0, x, r, get = 0, lost = 0, number; int t1 = 0, t2 = 0; char option, go; do { i++; srand(time(0)); x = rand() % 12 + 1; printf("=======================================================\n"); printf("Guesses Choice:\n"); printf("O-Odd E-Even L-Low M-Medium H-High N-Number\n"); printf("=======================================================\n"); printf("Enter your choice: "); scanf("%c", &option); getchar(); printf("Point at risk: "); scanf("%d", &r); switch (option) { case 'O': case 'o': printf("Odd number\n"); if( (x % 2) == 1) get = r; else lost = r; break; case 'E': case 'e': printf("Even number\n"); if( (x % 2) == 0) get = r; else lost = r; break; case 'L': case 'l': printf("Low number\n"); if(x <= 4) get = 2 * r; else lost = r; break; case 'M': case 'm': printf("Medium number\n"); if(x >= 5 && x <= 8) get = 2 * r; else lost = r; break; case 'H': case 'h': printf("High number\n"); if(x >= 9) get = 2 * r; else lost = r; break; case 'N': case 'n': printf("A number\n"); printf("Enter your number: \n"); scanf("%d", &number); if(x == number) get = 12 * r; else lost = r; break; default: printf("Try again!\n www.xlongjt.com"); } printf("The winning number is %d.\n", x); if(get > 0) printf("You won %d points.\n", get); else printf("You lost %d points.\n", lost); t1 += get; t2 += lost; printf("Continue (Y/N)? "); scanf("%c", &go); getchar(); } while (go == 'Y' || go == 'y'); printf("Total number of guesses: %d\n", i); printf("Your current point: %d\n", t1 - t2); system("pause"); }