C Programming Part 5: Functions and Control

Topics

  • Functions
  • Control flow (if, switch, for, while, do)
  • break & continue
  • Boolean expressions

Class Slides

Resources

Study Questions

  1. What is a function? Does it have a memory address? What is stored at that address?
  2. What makes up the type of a function?
  3. What is a static function?
  4. What happens when a function is called before its declaration? Does the compiler generate an error? Will your code work correctly? (https://www.geeksforgeeks.org/g-fact-95/)
  5. In C, what values represent false, and what values represent true?
  6. Are these two if statements equivalent? 
     if (x) {
     ...
 }

 if (x == 1) {
     ...
 }
  7. Are these two if statements equivalent? 
     if (x) {
     ...
 }

 if (x != 0) {
     ...
 }
  8. Does C have a boolean data type? What does <stdbool.h> provide?
  9. What is a conditional expression? What is the value of -1 ? 1 : 0?
  10. What happens if the omit the break statement in a switch case?
  11. What does break do? If you have a break statement in an inner loop, will it break out of the outer loop?
  12. What does continue do? How is it different than break?

  13. Are the three parts of a for loop required or optional?

  14. What does this code do? What happens if you remove the #include <stdlib.h> line? Does it still compile? Does it give the same behavior? Why? 
     #include <stdio.h>
 #include <stdlib.h>

 int main() {
   char str1[] = "1.5";
   char str2[] = "2.0";

   double d1 = atof(str1);
   double d2 = atof(str2);

   printf("Sum of values: %f\n", d1 + d2);
   return 0;
 }
  15. (T or F) This code will terminate after 5 iterations. 
     #include <stdio.h>

 int main() {
 int val = 5;
 while (val)
 printf("%d\n", val);
 val--;
 }
  16. How many times will this program print out the statement “did nothing”? 
     #include <stdio.h>
 int main() {
   int i = 10, j;
   if (i >= 0) // Do nothing if i < 0.
     for (j = 0; j < i; j++)
       if (j == 10) {
         printf("%d\n", j);
         return i;
       } else
         printf("did nothing.\n");
 }
  17. What will the following program will print out: 
     #include <stdio.h>
 int main() {
   int x = 10;
   if (x > 0)
     printf("1\n");
   else if (x > 1)
     printf("2\n");
   else if (x > 2)
     printf("3\n");
   else
     printf("4\n");
 }
  18. How many times will this program will print out “1”? 
     #include <stdio.h>

 int main() {
   int i = 2;
   switch (i) {
   case 1:
     printf("1\n");
     break;
   case 2:
     printf("1\n");
   case 3:
     printf("1\n");
     break;
   case 4:
     printf("1\n");
     break;
   }
 }
  19. (T or F) The functions p1 and p2 have the same behavior. 
     #include <stdio.h>
 void p1() {
   int x;
   x = 0;
   while (x < 5) {
     printf("looped\n");
     x++;
   }
 }

 void p2() {
   int x;
   for (x = 0; x < 5; x++)
     printf("looped\n");
 }

 int main() {
   p1();
   p2();
 }
  20. What is the last thing this program will print?: 
     #include <stdio.h>
 int main() {
   int x = 0;
   for (;;) {
     printf("%d\n", x++);
     if (x > 2)
       break;
   }
 }
  21. How many times will this program print hi!? 
     #include <stdio.h>
 int main() {
   int i = 0;
   do
     printf("hi!\n");
   while (i);
 }
  22. How many times will this program print “hi!”? 
     #include <stdio.h>
 int main() {
   while (1) {
     printf("hi!\n");
     break;
   }
 }
  23. How many times will this program print “hi!”? 
     #include <stdio.h>
 int main() {
   while (1) {
     printf("hi!\n");
     continue;
   }
 }
  24. How many times will this program print “hi!”? 
     #include <stdio.h>
 int main() {
   int i;
   for (i = 0; i < 10; i++) {
     if (i % 2)
       continue;
     printf("hi!\n");
   }
 }
  25. How many times will this program print “hi!”? 
     #include <stdio.h>
 int main() {
   int i;
   for (i = 0; i < 10; i++) {
     if (i % 2)
       break;
     printf("hi!\n");
   }
 }