#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

// Professora, altere aqui as variáveis globais para definir os primeiros 9
// dígitos do CPF e os primeiros 9 dígitos do ISBN-10

// Variáveis globais para definir os primeiros 9 dígitos do CPF e os primeiros 9
// dígitos do ISBN-10
const char *cpf_str = "123456789"; // Primeiros 9 dígitos do CPF como string
const char *isbn_str = "012345678"; // Primeiros 9 dígitos do ISBN-10 como string

// Função para converter uma string de dígitos em um array de inteiros
void str_to_int_array(const char *str, int *arr, int length) {
    for (int i = 0; i < length; i++) {
        arr[i] = str[i] - '0';
    }
}

// Função para calcular o primeiro dígito verificador do CPF
int calcular_primeiro_digito_verificador(int cpf[]) {
    int soma = 0;
    for (int i = 0; i < 9; i++) {
        soma += cpf[i] * (10 - i);
    }
    int resto = soma % 11;
    return (resto < 2) ? 0 : 11 - resto;
}

// Função para calcular o segundo dígito verificador do CPF
int calcular_segundo_digito_verificador(int cpf[]) {
    int soma = 0;
    for (int i = 0; i < 10; i++) {
        soma += cpf[i] * (11 - i);
    }
    int resto = soma % 11;
    return (resto < 2) ? 0 : 11 - resto;
}

// Função para calcular o dígito verificador do ISBN-10
int calcular_digito_verificador_isbn(int isbn[]) {
    int soma = 0;
    for (int i = 0; i < 9; i++) {
        soma += isbn[i] * (10 - i);
    }
    int resto = soma % 11;
    return (resto == 10) ? 'X' : resto;
}

int main() {
    // Converter strings de CPF e ISBN-10 em arrays de inteiros
    int cpf[9];
    int isbn[9];
    str_to_int_array(cpf_str, cpf, 9);
    str_to_int_array(isbn_str, isbn, 9);

    // Calcular os dígitos verificadores do CPF
    int cpf_completo[11];
    for (int i = 0; i < 9; i++) {
        cpf_completo[i] = cpf[i];
    }
    cpf_completo[9] = calcular_primeiro_digito_verificador(cpf);
    cpf_completo[10] = calcular_segundo_digito_verificador(cpf_completo);

    // Imprimir CPF
    printf("CPF: ");
    for (int i = 0; i < 11; i++) {
        printf("%d", cpf_completo[i]);
        if (i == 2 || i == 5) {
            printf(".");
        } else if (i == 8) {
            printf("-");
        }
    }
    printf("\n");

    // Calcular o dígito verificador do ISBN-10
    int isbn_completo[10];
    for (int i = 0; i < 9; i++) {
        isbn_completo[i] = isbn[i];
    }
    isbn_completo[9] = calcular_digito_verificador_isbn(isbn);

    // Imprimir ISBN-10
    printf("ISBN-10: ");
    for (int i = 0; i < 9; i++) {
        printf("%d", isbn_completo[i]);
        if (i == 0 || i == 3 || i == 4) {
            printf("-");
        }
    }
    if (isbn_completo[9] == 'X') {
        printf("X\n");
    } else {
        printf("%d\n", isbn_completo[9]);
    }

    return 0;
}
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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
}