C Language: data types [已解决]

蜡笔小烦

1. Write a printf and scanf statement for each of the following:
   
2. a. Print 200 with and without a sign.
   
3. b. Print 1.234 in a 9-digit field with preceding zeros.
   
4. c. Print 123.456789 in exponential notation with a sign(+ or -) and 3 digits of precision.
   
5. d. Read characters into array s until the letter p is encountered
   
6. e. Read a float value into variable num.
   
7. */
   
8. 
   
9. #include
   
10. void main()
    
11. {
    
12. int a=200;
    
13. unsigned int b=200;
    
14. const double c=1.234;
    
15. const double d=123.456789;
    
16. char s[50];
    
17. int count=0;
    
18. float f;
    
19. int i;
    
20. 
    
21. printf("rint 200 with and without a sign:\n";
    
22. printf("With a sign = %d\n",a);
    
23. printf("Without a sign = %d\n",b);
    
24. printf("\n";
    
25. 
    
26. printf("rint 1.234 in a 9-digit field with preceding zeros: ";
    
27. printf("%.9f\n",c);
    
28. printf("\n";
    
29. 
    
30. printf("rint 123.456789 in exponential notation with:\n";
    
31. printf("a sign(+ or -) and 3 digits of precision:\n";
    
32. printf("%.3Ef\n",d);
    
33. printf("\n";
    
34. 
    
35. printf("Read characters into array s until the letter p is encountered:\n";
    
36. do
    
37. {
    
38. scanf("%c",&s[count]);
    
39. count++;
    
40. }while(s[count]!='p');
    
41. printf("\n";
    
42. 
    
43. printf("Read a float value into variable num:\n";
    
44. scanf("%f",&f);
    
45. i = (int)(f + 0.5f);
    
46. printf("%d",i);
    
47. }

复制代码

没有error
可是output卡在bold字那个部分了。。。
打了p也不会停
看不到问题。。。

[ 本帖最后由 蜡笔小烦 于 18-10-2008 03:33 PM 编辑 ]

零翼

printf("\n";

少了 )

第一眼看到這個

cheng1986

1. do
   
2. {
   
3. scanf("%c",&s[count]);
   
4. count++;
   
5. }while(s[count-1] != 'p');

复制代码

index應該是count-1
s[count]還沒有被assign value

零翼

scanf("%c",&s[count]);

s 在這條line會被改寫

蜡笔小烦

原帖由 cheng1986 于 15-10-2008 11:01 PM 发表
do
{
scanf("%c",&s[count]);
count++;
}while(s[count-1] != 'p');index應該是count-1
s[count]還沒有被assign value

可以了
谢谢~

其实我不是很明白题目要求：
Write a printf and scanf statement for each of the following:
a. Print 200 with and without a sign.
b. Print 1.234 in a 9-digit field with preceding zeros.
c. Print 123.456789 in exponential notation with a sign(+ or -) and 3 digits of precision.
d. Read characters into array s until the letter p is encountered
e. Read a float value into variable num.

意思是说每一项都要有scanf吗？
如果是的话我做得是不是不符合要求了呢？

蜡笔小烦

原帖由 零翼 于 15-10-2008 11:23 PM 发表
scanf("%c",&s[count]);

s 在這條line會被改寫

啊？？？
不明
不好意思。。

cheng1986

現在這樣就對了
應該是問題有問題...

蜡笔小烦

原帖由 cheng1986 于 16-10-2008 06:38 PM 发表
現在這樣就對了
應該是問題有問題...

噢
是这样子


这一个部分
我不是很确定
是不是这样子做。。。
printf("rint 200 with and without a sign:\n";
printf("With a sign = %d\n",a);
printf("Without a sign = %d\n",b);
printf("\n";

[ 本帖最后由 蜡笔小烦 于 16-10-2008 06:57 PM 编辑 ]

onlylonly

print without sign
printf("%d", 200);

with sign
printf("%+d",200);

c. Print 123.456789 in exponential notation with a sign(+ or -) and 3 digits of precision.
printf("%+.3e", 123.456789);




[ 本帖最后由 onlylonly 于 17-10-2008 09:19 AM 编辑 ]

蜡笔小烦

原帖由 onlylonly 于 17-10-2008 09:12 AM 发表
print without sign
printf("%d", 200);

with sign
printf("%+d",200);

c. Print 123.456789 in exponential notation with a sign(+ or -) and 3 digits of precision.
printf("%+.3e", 123.456789);

...

原来是这样
谢谢