Why positive values turns negative - c

Question

I'm making some tests writing in a file.
Every single value numerical turns negative for no reason and i wont that.
I put for example: codigo : 1 and it always show the number -13312 , or codigo : 2 and the output is : -13312
How can i fix it?
#include <stdio.h>
int main() {
int codigo1[100];
int numero_telefone[100];
int numero_dependentes[100];
char nome[100];
char estado_civil[100];
FILE *fp;
if ((fp = fopen("nomes.txt", "a")) != NULL) {
printf("Indique o seu codigo de funcionario [0-100]: ");
scanf("%d", codigo1);
fprintf(fp, "Codigo funcionario: %d \n", codigo1);
printf("Inroduduza o seu nome: ");
scanf(" %s", nome);
fprintf(fp, "Nome: %s \n", nome);
printf("Insira o seu numero de telefone: ");
scanf("%d", &numero_telefone);
fprintf(fp, "Numero de telefone: %d \n", numero_telefone);
printf("Indique o seu estado civil: ");
scanf(" %s", &estado_civil);
fprintf(fp, "Estado civil: %s \n", estado_civil);
printf("Indique o numero de dependentes: ");
scanf("%d", &numero_dependentes);
fprintf(fp, "Numero dependentes: %d \n", numero_dependentes);
}
fclose(fp);
}

Answer 1

codigo is defined as an array of 100 integers. Which means it's essentially a pointer when passed to another function.
In this statement:
scanf("%d", codigo1);
codigo1[0] gets filled with the typed integer. The other 99 values inside that array are undefined. But codigo1[0] is assigned correctly.
But this statement:
fprintf(fp, "Codigo funcionario: %d \n", codigo1);
Is pushing the address of codigo1 onto the stack and the %d format specifier is used to interpret it as an integer. Also, a stack alignment issue if sizeof(&int) != sizeof(int) which is usually the case on 64-bit platforms. That can cause problems with printf statements using multiple format specifiers with corresponding parameters.
The easy fix is to pass the specific integer value you want to write to file:
fprintf(fp, "Codigo funcionario: %d \n", codigo1[0]);
Similar treatment is needed for your other statements. You should also consider if you really need to use arrays. The following works just as well:
int codigo1 = 0;
...
scanf("%d", &codigo1); // &codigo1 is the "address of" codigo1
fprintf(fp, "Codigo funcionario: %d \n", codigo1);