User:Wickedjargon/Learning C Q and A Style
Data Types[edit | edit source]
Is it true that this is an int (stands for integer)? 42 |
Yes. |
Is it true that this is an int? 0 |
Yes. |
Is it true that this is an int? -27 |
Yes. |
Is it true that this is an int? 3.14 |
No, that number includes a decimal point. 3.14 is a float. |
Is it true that this is an int? 42.0 |
No, 42.0 is a float. |
Are these ints? -0, +0 |
Yes! C allows all ints to be signed or unsigned. Zero is not a special case. -0, +0 are are signed ints. 0 is an unsigned int. |
Is it true that this is an int? 2,147,483,647 |
Yes. |
Is it true that this is an int? 2,147,483,648 |
No! ints cannot surpass 4 bytes. 2147483647 is the largest int that can fit onto 4 bytes of memory. |
How would this denary number be expressed in binary? +2147483647 |
0111 1111 1111 1111 1111 1111 1111 1111 The left most bit indicates the sign in. that 0 on the left means it's a positive number. There are
If you do not know binary, or need a review try A Crash Course in the Mathematics of Infinite Sets |
What is your definition of an int? |
int is a C data type that can hold only whole numbers, signed or unsigned, that can fit on to 4 bytes of memory. including 0, +0, -0, |
Which of the following is a float (floating point number)? 42., 40, 0, +0, -0 |
42., 40, 0 are floats. the float data type in C can represent both whole numbers and non-whole numbers. Floats cannot represent neither +0 nor -0. |
Is it true that this is a int? ∞ |
No. infinity has no representation in the int data type. However, ∞ is represented in the float data type. |
How is this represented in binary? ∞ |
+∞ is represented as 0 11111 0000000000 -∞ is represented as 1 11111 0000000000 |
Functions[edit | edit source]
Is it true that this is a function?
|
Yes. It can be compiled as-is. |
what does this mean/do? main |
It declares a function named 'main' |
What does this mean/do? () |
|
What does this mean/do? {} |
|
How many statements are there here? int pizza; int pizza = 1; |
A statement is preceded with ; therefore there are 2 statements. |
What does this do/mean? int pizza; int pizza = 1; |
|
How many statements are there here? int pizza; int pizza = 1; |
2 |
How many statements are there here? int pizza = 1; |
1 |
What does this mean/do? int pizza = 1; |
|
What does this mean/do?
#include <stdio.h>
int pepperoni;
int AddOneToInput(int pepperoni)
{
return pepperoni + 1;
}
int main()
{
printf ("%d",AddOneToInput(3));
}
|
... |
int pepperoni; |
the variable pepperoni of type int is initialized |
int AddOneToInput(int pepperoni) |
the function named AddOneToInput is declared an accepts one argument named pepperoni |
AddOneToInput(3) |
AddOneToInput(3) calls the function AddOneToInput with the argument 3 |
return pepperoni + 1; |
AddOneToInput takes the argument 3 and uses it in place of pepperoni. |
So this... return pepperoni + 1; |
becomes this... return 3 + 1; |
printf ("%d",AddOneToInput(3)); |
the function printf is called. prtinf's definition is within stdio.h. |
printf ("%d",AddOneToInput(3)); |
becomes.. printf ("%d",4); which becomes.. printf ("4"); and 4 is printed to the console. |