Practical C

Part 1: Examples from Above

1. Based on the example from Page 46 in "A Course in C". Compile and run the following programme.

   #include <stdio.h> main() { int array [10]; double rreal[10]; int i; for (i = 0; i < 10; i++) { array[i] = i; rreal[i] = i*0.1; printf("%d ", &array[i]); printf("%d\n", &rreal[i]); } printf("That's all!\n"); }

   What does the output illustrate?
   
   
2. Example from P58 of "A Course in C". Compile and run the following programme.

   /* Illustrates the difference between call-by-value and call-by-reference. */ #include <stdio.h> void call_by_value(int y) { y = 1; } void call_by_reference(int *y) { *y = 1; } main() { int x = 5; printf("original: x = %d\n", x); call_by_value(x); printf("should be same as before: x = %d\n", x); call_by_reference(&x); printf("should have changed: x = %d\n", x); }

   Make sure you understand the significance of the output!
   
   
3. Example from P60 of "A Course in C". Compile and run the following programme.

   /* Illustrates the passing of arrays to functions. */ #include <stdio.h> #define SIZE 5 int sum(int *data, int num_items) { int total, i; for (i = total = 0; i < num_items; i++) total = total + *(data + i); /* Try both versions of */ /* this line (see Arrays */ return total; /* as Args, above). */ } main() { int values[SIZE], i; for (i = 0; i < SIZE; i++) values[i] = i; printf("total = %d\n", sum(values, SIZE)); }

   Try both versions of this program (see Arrays as Arguments, above); verify that they give the same results.

Part 2: Run-time Errors

The remaining examples are mainly to illustrate run-time errors, though there also compile-time errors.