if bugando inside the vector for in C

Question

Mine ifs within the for vector are bugging and at the end of the execution of the program showing a completely random number. Follow the code:

//Exercicio_08
#include <conio.h>  
#include <stdio.h>  
#define max 8 
//Codigo  
main(){  
    int i;  
    int a[max];  
    int par;  
    par = 0;  
    //entrada vetor A     
    for(i=1; i<=max; i++){  
        printf("\nDigite o %i elemento do vetor A: ", i);  
        scanf("%i",& a[i]);  
    }  

    //mostra o vetor A  
    printf("\n");  
    for(i=1; i<=max; i++){    
        printf("%i ", a[i]);  
    }  
    for(i=1; i<=max; i++){  
        if(a[i] % 2 == 0){  
        printf("\nPar: %i", & a[i]);  
        par = par + 1;      
        }  
    }  
printf("\nQuantidade de pares: %i", &par);          
getch();  
}

Answer 1

Do not use conio, this is obsolete only available in compilers considered bad today.

You can use %d to deal with whole which is more common to do not accept hexadecimals.

The main problem that even prevents compiling is that you are using O operator & in the printf(). This operator takes the address of the data, and is trying to print the data, which gives conflict. He probably thought he should do the same as in scanf(). There it’s different. You don’t pass the data to the function, you pass the address wherever the data is stored.

As said by Leandro Godoy Rosa, the array should start at 0 and go up to your size minus 1. It may seem silly and works in some cases going from 1 to Len. But you’re taking something you shouldn’t, violating the memory.

I improved the code.

#include <stdio.h>
#define max 10

int main(void) {
    int a[max];
    for (int i = 0; i < max; i++) {
        printf("\nDigite o %i elemento do vetor A: ", i);
        scanf("%d", &a[i]);
    }
    printf("\n");
    for (int i = 0; i < max; i++) {
        printf("%d ", a[i]);
    }
    int par = 0;
    for (int i = 0; i < max; i++) {
        if (a[i] % 2 == 0) {
            printf("\nPar: %d", a[i]);
            par++;  
        }
    }
    printf("\nQuantidade de pares: %d", par);       
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.