#include <stdio.h> // biblioteca para ler e exibir valores (imprimir na tela)
#include <stdlib.h> // para fazer operações dentro do C (matemática e outras)
#include <locale.h> // Biblioteca para utilizar acentos no C
// Professor Douglas - [email protected]

void main (){ //Funcao MAIN primeira função (por padrao) que roda quando e executado do tipo VOID para ser vazio
    setlocale(LC_ALL,""); // Função para usar acentos - permite acentos
    printf("Olá, amanhã haverá aula"); // comando printf que imprime na tela
         printf("\n"); // pular uma linha
    // a seguir outras maneiras de exibir na tela print
    // Exibição de textos dentro do código C:
    // printf("Texto \n"); -- entre parenteses e aspas duplas e pular linha

    // valor de uma variavel (recordar o VISUALG):
    // printf("%d",a); -- onde %d serve para número INTEIROS (%d) e a letras "a" trata-se no nome da variável, isso após a virgula.
    int w = 32; // declarar a variavel do tipo inteiro com valor de 32
    int y = 8;
    printf("%d",w);
            printf("\n");
    printf ("%d", y);
            printf("\n");
    printf("%d", w+y);
            printf("\n");

    // Juntando
    printf(" A subtração das variáveis é: %d \n \n", w-y);


    // Agora vamos ler um valor para a variável W utilizando o comando scanf
    printf(" Digite um novo valor para W: \n" );
    scanf("%d", &w); // & = a endereço na memória - A linha diz "escaneie um valor inteiro para a variável w e atribua um novo valor"
    printf("\n Agora o valor de w é: %d \n",w);
    printf("\n E a nova subtração das variáveis é: %d \n \n", w-y);

    // Criando linhas
    printf("==================================== \n");
    printf("==========PROGRAMA EM C============= \n");
    printf("=======MODULO CARAGUATATUBA========= \n");
    printf("#################################### \n \n");
}

C Language online compiler

Write, Run & Share C Language code online using OneCompiler's C online compiler for free. It's one of the robust, feature-rich online compilers for C language, running the latest C version which is C18. Getting started with the OneCompiler's C editor is really simple and pretty fast. The editor shows sample boilerplate code when you choose language as 'C' and start coding!

Read inputs from stdin

OneCompiler's C online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample C program which takes name as input and print your name with hello.

#include <stdio.h>
int main()
{
    char name[50];
    printf("Enter name:");
    scanf("%s", name);
    printf("Hello %s \n" , name );
    return 0;
    
}

About C

C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.

Key features:

  • Structured Programming
  • Popular system programming language
  • UNIX, MySQL and Oracle are completely written in C.
  • Supports variety of platforms
  • Efficient and also handle low-level activities.
  • As fast as assembly language and hence used as system development language.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition if-else is used.

if(conditional-expression) {
   // code
} else {
   // code
}

You can also use if-else for nested Ifs and if-else-if ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to if-else-if ladder.

switch(conditional-expression) {    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
...    
    
default:     
 // code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  // code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition) {  
 // code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {
  // code 
} while (condition);

Arrays

Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.

Syntax

One dimentional Array:

data-type array-name[size];

Two dimensional array:

data-type array-name[size][size];

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.

Two types of functions are present in C

  1. Library Functions:

Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,

  1. User defined functions:

User defined functions are the ones which are written by the programmer based on the requirement.

How to declare a Function

return_type function_name(parameters);

How to call a Function

function_name (parameters)

How to define a Function

return_type function_name(parameters) {  
  //code
}