这个数组求和哪里还有问题

#include <stdio.h>

int main(void)
{
int a[5]={5,4,3,2,1};
int i,sum;
for (int i=0;i<5;i++)
{
sum=sum+a[i];
}
printf("sum=%f\n",sum);
return 0;
}

#include <stdio.h>

int main(void)
{
    int a[5] = {5, 4, 3, 2, 1};
    int i, sum = 0;
    for (i = 0; i < 5; i++)
    {
        sum = sum + a[i];
    }
    printf("sum=%d\n", sum);
    return 0;
}