C

Video link: https://www.youtube.com/watch?v=j-_s8f5K30I

Declaring Variables

A declaration consists of a type and a list of variables as shown below:

main(){
	int lower, upper, step;
	float fahr, celsius;
}

Here we declare 3 variables that will contain integers, lower, upper, and step. Then we declare two variables that will contain floating point numbers, fahr and celsius.

• ints can be between -32768 and +32767, they are a signed 16-bit number
• floats are 32-bits and can be between 10^-38 and 10^+38

Other Var Types

Type	Description
char	a 1 byte character
short	short int
long	long int
double	double precision float

While Loops

while(i < j){
	i = 2 * i;
}

Difference Between Constants and Variables

Constant = a fixed value, does not change Variable = can change over time

Declaring a constant

#define LOWER 0

Useful Programs

getchar()

• gets the next input character each time it is called In the example below c will contain character that was inputed.

char c
c = getchar()

putchar()

• writes a character to stdout.

putchar(c)