Math 211    Test 2, April 9, 1997

Pink version.


Instructions.
 
Please enter your AFS-id and ID number.
 
Problems 1 to 8 worth 10 points each.

With the input specified for the given problem,
give your output in EXACTLY the same way the
computer will generate; the output should be
three lines or less, so you should have enough
space for each problem.

Problem 9 worth a total of 20 points. Each sub
problem worth 4 points, there is no partial credit
for sub problems.



Problem 1: no input

#include <stdio.h>
#define N 6

main()
{
	int a[N] = {2, 2, 3, 3, 4, 4};
	int j, k;

        for ( j = 1; j < 6; j++){
            printf("%d ", a[j]);
            }

        k = 0;
        for ( j = 0; j < 6; j++){
            k += a[j];
            }

        printf("\n");

	printf("%d\n", k/N);
  
        return 0;
}





Problem 2:  no input

#include <stdio.h>

main()
{
        int j = 17, k = 23;
        int *p, *q;

        p = &k;
        printf("The first value is %d \n", *p);

        q = p;
        p = &j;
        *p += *q;
        printf("The second value is %d \n", *p);

        return 0;
}




Problem 3:  INPUT  University of Notre Dame\n


#include  <stdio.h>
#include <ctype.h>

#define  SIZE 200

main()
{
        char message[SIZE];
        char *p;
 
        printf("Enter a message: ");
        
        p = message;
        for ( *p = getchar(); *p != '\n'; ){
             *(++p) = getchar();
             }

        for ( p = message; *p != '\n'; p++){
             putchar(*p);
             }
        printf("\n");

        for ( p = message; *p != '\n'; p++){
             putchar(toupper(*p));
             if ( *p == ' ') break;
             }
        printf("\n");

        return 0;
}




Problem 4: no input


#include <stdio.h>
#include <string.h>

main()
{
	char *days[] = {"Sunday", "Monday", "Tuesday", 
                      "Wednesday", "Thursday",
                      "Friday", "Saturday"};

        char mess[500];
        
        printf("%s\n", days[0]);

        strcpy( mess, days[1] );
        puts(mess);

        strcat( mess, " " );
        strcat( mess, *(days+3) );
        strcat( mess, " " );
        strcat( mess, days[5] );
        puts(mess);
        
        return 0;
}




Problem 5:  The program is compiled by the command
     cc -o tellme problem5.c
 The user type the following command:
     tellme how 

Here is the code problem5.c

#include  <stdio.h>

int strcount(char const * const str);

main(int argc, char *argv[])
{
        int j, k;
   
        for ( j = 0; j < argc; j++){
             k = strcount( argv[j] );
             printf("The word");
             printf(" \"%s\" ", argv[j]);
             printf("contains %d characters", k);
             printf(" (including spaces)\n");
             }
 
        return 0;
}

int strcount(char const * const str)
{
        int j;
  
        for (j = 0;  j < 500;  j++){
             if  (str[j] == '\0')  return j;
             }
       
}




Problem 6:  no input 


#include <stdio.h>

int k = 2;

int modify(int j);

main()
{
     int j = 2, m = 4;

     j = modify(j);
     printf("j is now %d\n", j);   
     
     m = modify(m);
     printf("m is now %d\n", m);   

     k = modify(k);
     printf("k is now %d\n", k);   
     
     return 0;
}

int modify(int j)
{
     k += 3;
     j *= 3;
     return j;
}




Problem  7:  no input


#include <stdio.h>
 
#define AREA_T(x,y)  (x)*(y)/2
#define AREA_R(x,y)  (x)*(y)
#define AREA_C(x,y)  3.14*(x)*(x)
 
#define TRIANGLE 0
#define RECTANGLE 1
#define CIRCLE 1
 
#define AREA(x,y)     ( TRIANGLE ? AREA_T(x,y): \
                      RECTANGLE ? AREA_R(x,y): \
                      AREA_C(x,y)   )
 
 
 
main()
{
        float  x = 2.0, y = 5.0;
 
        printf("The area is %.2f\n", AREA_C(x,y));

        printf("The area is %.2f\n", AREA(x,y));

        return 0;
}




Problem 8:  INPUT  6\n

#include <stdio.h>

typedef int Bool ;
void modify(int a[], int n);
void scrmsg(int b);

main() 
{ 
     int a[] = {1, 1, 2, 2, 2};
     int k, b = 0;
     int *p;

     printf("Please add the following numbers: ");
     for ( p = a; p < a + 4; p++){
         printf("%d ", *p);
         b += *p;
         }
     printf(" = ");

     p = &k;
     scanf("%d", p);
     scrmsg(!(*p - b));
}		

void scrmsg(Bool b)
{
  b?
  printf("Great, no mistakes!\n") :
  printf("Oops, there are mistakes!\n");
} 




Problem 9. Give the answers 

The following problem is a modification of Page 182,
number 8.

(1) Which of the following is a valid declaration
of a function that returns nothing and has one float
variables?
(NO CREDIT will be given if more than two answer is
given. If there are more than two correct answers,
choose either one of the correct answers).

(a) void f(int x);    (b) void f(float);
(c) void f(x);        (d) f(float x);



The following problem is a modification of Page 235,
number 7.

(2)  #define TRUE 1
     #define FALSE 0
     int a[6];
     int *p;
     p = a;

The above assignments have been made.  Which of the
following statement would return TRUE?
(NO CREDIT will be given if more than two answer is
given. If there are more than two correct answers,
choose either one of the correct answers).

(a) p == a[0];           (b)  p == &a;
(c) *p == a[0];          (d)  p[0] == a; 






The following problem is a modification of Page 269,
number 2.

(3)   char *p = "abc";

The above assignments have been made.  Which of the
following is legal?
(NO CREDIT will be given if more than two answer is
given. If there are more than two correct answers,
choose either one of the correct answers).

(a) putchar(p);                   (b) putchar(*p);
(c) printf("%s", *p);             (d) puts(*p);
  



(4)  int i,j;
  int a[6];
  int *p, *q ;

The above assignments have been made.  Which of the
following is illegal?
(NO CREDIT will be given if more than two answer is
given. If there are more than two correct answers,
choose either one of the correct answers).
 
(a) p = &i;     (b)  q = *(a+3);     (c)  p = &a[2];
(d) *q = *p;              (e)  *p = *&j; 
 





(5)
  #define FALSE 0
  #ifdef FALSE
     #define M 10
  #else
     #define M 80
  #endif

Answer M =