#include <stdio.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
// Função para calcular e gerar o CPF completo
// Os 9 primeiros dígitos: inscrição inicial (aleatórios ou fornecidos pelo usuário)
// O 10º dígito: primeiro dígito verificador
// O 11º dígito: segundo dígito verificador
void gerarCPF(char *cpf, int regiao) {
if (strlen(cpf) != 9) {
printf("Erro: O CPF deve conter exatamente 9 dígitos.\n");
return;
}
printf("\n\n=== Gerando CPF... ===\n");
// Cálculo do primeiro dígito verificador
int somaParcial = 0, primeiroDV = 0, segundoDV = 0;
for (int i = 0; i < 9; i++) somaParcial += (cpf[i] - '0') * (i + 1);
primeiroDV = somaParcial % 11;
if (primeiroDV == 10) primeiroDV = 0;
cpf[9] = '0' + primeiroDV;
printf("Primeiro dígito verificador (D1): %d\n", primeiroDV);
// Cálculo do segundo dígito verificador
somaParcial = 0;
int peso = 11;
for (int i = 0; i < 10; i++) somaParcial += (cpf[i] - '0') * peso--;
segundoDV = (somaParcial * 10) % 11;
if (segundoDV == 10) segundoDV = 0;
cpf[10] = '0' + segundoDV;
printf("Segundo dígito verificador (D2): %d\n", segundoDV);
cpf[11] = '\0'; // Adiciona o caractere de terminação
}
// Função para calcular o dígito verificador de um código ISBN-10
int calcularISBN(char *codigo) {
int somaParcial = 0;
if (strlen(codigo) != 9) {
printf("\nErro: O código ISBN deve conter exatamente 9 dígitos.\n");
return -1;
}
// Calcula a soma ponderada dos dígitos (pesos de 10 a 2)
for (int i = 0; i < 9; i++) {
if (codigo[i] < '0' || codigo[i] > '9') {
printf("\nErro: O código ISBN contém caracteres inválidos.\n");
return -1;
}
somaParcial += (codigo[i] - '0') * (10 - i);
}
// Calcula o dígito verificador
int resto = somaParcial % 11;
int digitoVerificador = (11 - resto) % 11;
// Retorna o dígito verificador ('X' para 10)
if (digitoVerificador == 10) {
return 'X';
} else {
return '0' + digitoVerificador;
}
}
int main() {
int opcao = 0;
int execucoes = 0;
while (1) {
printf("======= MENU ========\n");
printf("Escolha uma opção:\n1. Gerar CPF\n2. Calcular dígito verificador de código ISBN\n\n");
scanf(" %d", &opcao);
execucoes++;
switch (opcao) {
case 1:
char cpf[12];
printf("Digite os 9 primeiros dígitos do CPF: ");
scanf("%9s", cpf);
gerarCPF(cpf, 8);
printf("\nCPF Gerado: %c%c%c.%c%c%c.%c%c%c-%c%c\n\n",
cpf[0], cpf[1], cpf[2],
cpf[3], cpf[4], cpf[5],
cpf[6], cpf[7], cpf[8],
cpf[9], cpf[10]);
break;
case 2:
char isbn[10];
printf("Digite os 9 primeiros números do código ISBN: ");
scanf(" %s", isbn);
int digitoVerificador = calcularISBN(isbn);
if (digitoVerificador == -1) {
printf("\nErro ao calcular o dígito verificador. Tente novamente.\n");
break;
}
printf("\n\nDígito verificador: %c\n", digitoVerificador);
printf("Código ISBN completo: %c%c%c%c%c%c%c%c%c%c\n\n",
isbn[0], isbn[1], isbn[2],
isbn[3], isbn[4], isbn[5],
isbn[6], isbn[7], isbn[8],
digitoVerificador);
break;
default:
printf("Escolha uma opção válida.\n");
break;
}
if (execucoes == 2) {
break;
}
}
return 0;
}
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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.
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.
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;
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement){
// code
}
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
}
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);
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.
data-type array-name[size];
data-type array-name[size][size];
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
Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,
User defined functions are the ones which are written by the programmer based on the requirement.
return_type function_name(parameters);
function_name (parameters)
return_type function_name(parameters) {
//code
}