PAT甲级 1001

1001 A+B Format （20 分）

Calculate a+b and output the sum in standard format -- that is, the digits must be separated into groups of three by commas (unless there are less than four digits).

Input Specification:

Each input file contains one test case. Each case contains a pair of integers a and b where −10​6​​≤a,b≤10​6​​. The numbers are separated by a space.

Output Specification:

For each test case, you should output the sum of a and b in one line. The sum must be written in the standard format.

Sample Input:

-1000000 9

Sample Output:

-999,991



两种思路，第一种是今天写的，将结果预处理好存在字符串里直接输出

 1 #include
 2 #include
 3 #include
 4 using namespace std;
 5 int main()
 6 {
 7     long long a,b,c;
 8     char s[100];
 9     while(scanf("%lld%lld",&a,&b)!=EOF)
10     {
11         c=a+b;
12         int flag=0;
13         if(c<0)
14         {
15             flag=1;
16             c=0-c;
17         }
18         int l=0;
19         int g,w=0;
20         while(c)
21         {
22             g=c%10;
23             c/=10;
24             s[l++]=g+'0';
25             w++;
26             if(w%3==0)s[l++]=',';
27         }
28         if(a+b==0)cout << "0" <<endl;
29         else
30         {
31             if(flag)cout <<"-";
32             if(s[l-1]!=',')cout << s[l-1];
33             for(int i=l-2;i>=0;i--)
34                 cout << s[i];
35             cout <<endl;
36         }
37     }
38 }

 

另一种是去年写的，一边输出一边加逗号，翻看以前的代码被自己秀到了。。。

 1 #include
 2 #include
 3 #include
 4 using namespace std;
 5 int main()
 6 {
 7     int a,b,c,d=1;
 8     while(scanf("%d%d",&a,&b)!=EOF)
 9     {
10         a+=b;
11         c=0;
12         d=1;
13         if(a<0){printf("-"); a=0-a;}
14         b=a;
15         while(a/=10)
16         {
17             c++;
18             d*=10;
19         }
20         c++;
21         for(;c>0;)
22         {
23             printf("%d",b/d);
24             b%=d;
25             d/=10;
26             c--;
27             if(!(c%3)&&c)printf(",");
28         }
29         printf("\n");
30     }
31     return 0;
32 }