Printing & inputs

A function that takes an integer as an argument and prints it:

• void means this function doesn't return a value.
• printNumber is the name of the function.
• int num is the parameter; it takes an integer.
• printf is a standard I/O function used to print the number.

void printNumber(int num) {
    printf("%d\n", num);
}

A function that takes two integers and returns the sum:

• int indicates that this function returns an integer.
• addNumbers is the function name.
• int num1, int num2 are parameters; the function takes two integers.
• return statement returns the sum of num1 and num2.

int addNumbers(int num1, int num2) {
    return num1 + num2;
}

Main function

• Every C program must have a main function. This is where your program starts execution.
• Inside main, you can call the functions you've defined. For example:

int main() {
    printNumber(5);
    int sum = addNumbers(3, 4);
    printf("Sum is: %d\n", sum);
    return 0;
}

• return 0 indicates that the program executed successfully.

Converting Celsius to Fahrenheit

#include <stdio.h>

int main(){
    //Initialize variables with integer types
    int fahr, celcius;
    int lower, upper, step;

    //Declare values for variables. Start at "lower" for the loop. And end the loop with "upper". Increase farenheight by 20 each time.
    lower = 0;
    upper = 300;
    step = 20;
    fahr = lower;

    //Farenheight will start with the value of 0. Then the value of celcius will be caclulated by a formula which converts farenheight to celcius
    while(fahr <= upper){
        celcius = 5 * (fahr-32) / 9;
        //Use %d to reference a parameter in order
        printf("%d\t%d\n", fahr, celcius);
        //Increase by 20, looping through 16 iterations
        fahr = fahr + step;
    }
    return 0;
}