# C Stuff to remember

Here you find some C operators that you will use very often, while learning I was always looking what some of this stuff means.

So I just decided to make a small Blogpost about it so that I always know where I can look those operators and other stuff up.

C Shortcuts for incrementing and scaling variables

x++; //Increments x, Evaluates to x.

++x; //Increments x, Evaluates to x+1.

x--; //Decrement x, evaluates to x.

--x; //Decrement x, evaluates to x-1.

x+=3; //Add three to x.

x-=7; //Substract seven from x.

x*=2; //Multiply x by two.

x/=2; //Divide x by tw0.

x%=2; //Replace x with modulo.

C True or False definition

!x //Not x.

x == y //x equals y.

x != y //x is not equal to y.

x < y //x is less than y.

x <= //x is less than or equal to y

x || y //x or y.

x && y //x and y.

x > y || y >= z //x is greater than y or y is greater than or equal to z.

C trinary operator

The expression:

x ? a : b

evaluates to a if x is true, and to b if x is false.

### Example

#include

#include

int main(){

double x = 49;

printf("The truncated square root of x is %g.\n",

x > 0 ? sqrt(x) : 0);

}

The trinary conditional operator has a short-circuit(lazy) behavior:

if *x <= 0* , then sqrt(x) is never evaluated.

Variable placeholders and special characters

\n //New line.

\t //A tab.

%i //Insert an integer value.

%g //Insert a real number in general format.

%s //Insert a string of text here.

%% //Insert a plain percent sign.

While and for loop

#include

int main(){

int i = 0; //Declaring the variable i.

while (i < 10){ //Initializing the while loop.

printf("This is: Loop %i\n", i); //Prints which loop were at.

i++ //Increments i with each loop.

}

}

In the above example if *i* for example would be eleven, then the body of the while loop would be skipped. If we want a while loop to run at least once then there is the *do-while loop*.

Do while loop example

#include

void loops(int max){ //Declaring the max variable inside the loops function.

int i = 0;

do { //Tell the programm what to do.

printf("Hello you.%i\n", i);

i++;

} while (i < max); //Do it only as long as i is smaller than max.

}

int main(){

loops(3); //Prints "Hello you." three times.

loops(0); //Prints "Hello you." one time.

}

A while loop is made out of three parts.

- Initialize the variable *(int i=0)*

- Testing the condition *(i < 10)*

- Increment the variable *(i++)*

For loop example

The for loop uses the exact same steps as the while loop *(Initialize, test, increment)*, but encapsulates them in one place:

#include

int main(){

for (int i=0; i < 10; i++);{ //Initialize, test, increment.

printf("Hello you.%i\n", i);

}

}