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CSCE150A

First Program

Variables

Computer Science & Engineering 150A

Problem Solving Using Computers – Laboratory

Lecture 02 – Programs and Variables

Derrick Stolee

Spring 2009

dstolee@cse.unl.edu

CSCE150A

First Program

Variables

First Program: The Code

#include <stdio.h>

/* this is a comment! */

int main(void)

{

printf(”This lab is so cool!\n”);

}

CSCE150A

First Program

Variables

Variables: Integers

int variablename = number;

Stores integer values, 0 , 1 , − 1 , 10242.

Takes 4 bytes.

CSCE150A

First Program

Variables

Variables: Floats

float variablename = number.decmials;

Stores decimal values, 0. 0 , 1. 234 , − 1234. 5.

Takes 4 bytes.

CSCE150A

First Program

Variables

Variables: Characters

char variablename = ’c’;

Stores letters, ’A’, ’b’, ’0’, ’\n’, ’\0’.

Takes 1 byte.

CSCE150A

First Program

Variables

Printing

printf("string", parameters, ... );

Outputs “string” with a few extras... (%)

Placeholder Variable Type

%d int

%f float

%lf double

%c char

CSCE150A

First Program

Variables

Cheat Sheet

Var Name Stores Size Placeholder

int Integers 4 bytes %d

float Decimals 4 bytes %f

double Decimals (better) 8 bytes %lf

char Letters 1 byte %c

#include <stdio.h>

int main(void) {

...

}

gcc -o program file.c