Midterm Exam (1)
C++ Programming
NCNU CSIE

Date: March 4th, 2009
Time: 08:30-10:30
Open book; turn off computer & mobile phone

1. What will be the output of the following program?

   #include <iostream>
   using std::cout;
   using std::endl;
   
   int main()
   {
     cout << 3 << 3 << 3 << endl;
     cout << (3 << 3 << 3) << endl;
     cout << 3 << (3 << 3) << endl;
     cout << (3 << (3 << 3)) << endl;
   }
   
   

2. Check whether the following program has any syntax mistake. If yes, point out the mistakes and correct them; if no, predict the output of the program.

   #include <iostream>
   using std::cout;
   using std::endl;
   
   int main()
   {
       int i, j;
       for (i=0; i<6; i++)    
          for (j=0; j<6; j++);
              cout << "A";
          cout << endl;    
       return 0;
   }

3. Check whether the following program has any mistake. If yes, point out the mistakes and correct them; if no, predict the output of the program.

   #include <iostream>
   using namespace std;
   
   int main( void )
   {   int i=0, nums[10]={ 1, 8, 9, 5 };
       while( i<10 )
       {
           if( i%2 )
           {
               ++i;
               break;
           }
           nums[i++]=i;
       }
       for (i=0;i<10;)    
           cout << nums[i++] << " ";
           cout << endl;
       return 0;
   }

4. Determine whether the following code is correct or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).

   // pointer to function
   #include <iostream>
   using std::cout;
   using std::endl;
   
   int sum(int a, int b)
   { return a+b;
   }
   
   int product(int a, int b)
   { return a*b;
   }
   
   int main()
   {
       int *pfun(int, int) = sum;
       cout << pfun(4, 8) << endl;
       pfun = product;
       cout << pfun(4, 8) << endl;
   }

5. Check whether the following program has any mistake. If yes, point out the mistakes and correct them; if no, predict the output of the program.
   
   #include <iostream> 
   using std::cout; 
   using std::endl; 
   int sum(int x1=1, int x2=2, int x3=3, int x4=4); 
   // Supply default values of parameters 
   int main(void)
   {
   	cout << sum(300, 15) << endl; 
   } 
   int sum(int x1, int x2, int x3, int x4) 
   { 
       return x1 + x2 + x3 + x4; 
   }
   

6. What will be the output of the following program?

   // bin2dec.c
   #include <iostream>
   using std::cout;
   using std::endl;
   
   int main()
   {
       char b[] = "11100110000";
       int n=0, i=0;
       while (b[i])
           n = (n<<1) + b[i++] - '0';
       cout << n << endl;
       return 0;
   }
   

7. What will be the output of the following program?

   #include <iostream>
   using std::endl;
   using std::cout;
   
   int main()
   {
       char a[]="HELLO, WORLD!";
       const int k = sizeof(a);
       int sum = 0;
       for(int i=0;i<k;i++)
           sum += a[i];
       cout << "k= " << k << endl;
       cout << "sum= " << sum << endl;
   
       return 0;
   }
   

8. Check whether the following program has any mistake. If yes, point out the mistakes and correct them; if no, predict the output of the program.

   #include <iostream>
   #define N 10
   using std::cout;
   
   void dout(int n)
   {
   	   if(n<0)
           cout << "(" << n << ")";
       else
           cout << n;
   }
   
   int main()
   {
       int M[N], D[N], Q[N], R[N], A[N], B[N];
       int i = 0;
       M[0] = 1610; D[0] = 590;
       do
       {
           Q[i] = M[i] / D[i];
           R[i] = M[i] - Q[i]*D[i];
           M[i+1] = D[i];
           D[i+1] = R[i];
       } while (R[i++] > 0);
   
       i-=2; A[i] = 1; B[i] = -Q[i];
       cout << R[i];
       while (1)
       {
           cout << "\t=\t";        dout(A[i]);
           cout << "*";            dout(M[i]);
           cout << "+";            dout(B[i]);
           cout << "*";            dout(D[i]);
           cout << "\n";
   
           if (i==0) break;
           A[i-1] = B[i];
           B[i-1] = A[i] - B[i]*Q[i-1];
           i--;
       }
   }

9. Check whether the following program has any mistake. If yes, point out the mistakes and correct them; if no, predict the output of the program.
   
   

   // Pass-by-value
   #include <iostream>
   using std::cout;
   using std::endl;
   
   void test(char p[])
   {  cout << p ;
   }
   
   int main()
   {
       char *name = "####";
       while (*name)
           test(name++);
       cout << endl;
   }
   
   

   
   
10. Determine whether the following code is correct or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).

    #include <iostream>
    using std::cout;
    
    void eatspaces(char* str)
    {
        int i = 0, j = 0;
        while ((*(str+i) = *(str + j++)) != '\0')
            if (*(str + i) != ' ')
               i++;
        return;
    }
    
    int main()
    {
        int i = 0;
        char msg[] = "National Chi Nan University";
        eatspaces(msg);
        for (i=0; msg[i] != '\0'; i++);
            cout << i << '\n';
    }