How to convert array of integers into an integer in C?

Question

How can I convert an array of 6 integers into a single integer. Example provided below of what I want to do.

Array: {0, 1, 2, 3, 4, 5, 6}

Integer: 123456

Thank you!

Answer 1

Try this:

int i, k = 0;
for (i = 0; i < n; i++)
    k = 10 * k + a[i];

where n is the length of the array. This is true, however, when the array is short enough otherwise you would get an int overflow.

Answer 2

Here is a function I made

int array_to_num(int arr[],int n){
    char str[6][3];
    int i;
    char number[13] = {'\n'};

    for(i=0;i<n;i++) sprintf(str[i],"%d",arr[i]);
    for(i=0;i<n;i++)strcat(number,str[i]);

    i = atoi(number);
    return i;
} 

where str[6][3] means there are 6 elements that can hold 2 digit numbers, change it to suit your needs better. Also n is the size of the array you put into the function. Use it like this:

int num[6] = {13,20,6,4,3,55};
int real_num;
real_num = array_to_num(num,6);

real_num will now be 132064355