## C Documentation

```int main() {
/* comments like these are ignored by the compiler */
printf("Hello, World! \n");
return 0;
}
```

### Printing

```int main() {
/* the next line will print Hello World! to the console */
printf("Hello, World! \n");

return 0;
}
```

### Comparison Operators

```/* Comparison operators return booleans (true/false values) */
/* is x equal to y */
x == y
/* is x not equal to y */
x != y
/* is x greater than y */
x > y
/* is x greater than or equal to y */
x >= y
/* is x less than y */
x < y
/* is x less than or equal to y */
x <= y

```

### If Statement

```if (boolean_expression) {
/* statement(s) will execute if the boolean expression is true */
}
#include <stdio.h>

int main() {

/* local variable definition */
int a = 1;

/* check the boolean condition */
if (a < 100) {
/* if condition is true then print the following */
printf("a is less than 100\n" );
}

printf("a is : %d\n", a);

return 0;
}
```

### Math

```/* Operators: */
-   Subtraction
*   Multiplication
/   Division
%   Modulus (Remainder)

/* Examples: */
int z = x + y;
int w = x * y;

x++

/* Decrement (subtract one) */
x--

/* Absolute value */
int value = int abs(int x)

/* Square Root */
double sqrt = double sqrt(double x)

/* Rounding */
/* round() can be used to round numbers */
float pi = 3.14;
float roundedPi = round(pi);
/* print out 3: */
printf(roundedPi);

/* Example */
#include <stdio.h>
#include <math.h>

int main () {

int a = 1;
int b = 11;

if (a + b < 100) {
/* if condition is true then print the following */
printf("a + b is less than 100\n" );
}

return 0;
}

```

### Arrays

```/* syntax to declare an array */
type arrayName [ arraySize ];

/* declare a 7-element array called weights */
double weights;

/* initialize array */
double weights = {10.0, 200.0, 45.4, 70.0, 99.0};

/* assign 4th elements of the ages array to be 33.0 */
weights = 33.0;

/* index into array to access the third element */
double third = weights;
```

### While Loop

```/* while loop syntax */
while(condition) {
statement(s);
}

/* while loop example */
#include <stdio.h>

int main() {

/* local variable definition */
int a = 1;

/* while loop execution */
while (a < 100) {
printf("a is still less than 100!");
a++;
}

return 0;
}
```

### For Loop

```/* for loop syntax */
for (initialize; condition; increment) {
statement(s);
}

/* for loop example */
#include <stdio.h>

int main() {

int a;

/* for loop execution */
for (a = 1; a < 100; a++) {
printf("value of a is: %d\n", a);
}

return 0;
}
```

### Function

```#include <stdio.h>

/* declare the function */
int min(int num1, int num2);

int main() {

/* local variable definition */
int a = 100;
int b = 200;
int minimum;

/* calling the min function and assigning minimum value found to minimum */
minimum = min(a, b);

printf( "Minimum value: %d\n", minimum );

return 0;
}

/* function returning the minimum between two numbers */
int min(int num1, int num2) {

/* local variable declaration */
int result;

if (num1 < num2) {
result = num1;
}
else {
result = num2;
}

return result;
}
```