Assigning value to a variable not working

Question

I have a variable and a method:

char alfabet2[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; 

char is_mixed(char* str) {
    for (int x = 0; str[x] != '\0'; x++)
    {
        if (str[x] >= 'a' && str[x] <= 'z') {
            alfabet2[] = "abcdefghijklmnopqrstuvwxyz"
        } else if (str[x] >= 'A' && str[x] <= 'Z') {
            alfabet2[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        } else if (str[x] >= '0' && str[x] <= '9') {
            alfabet2[] = "0123456789"
            }
    } return alfabet2;
}

And I have these errors:

Can someone please help me to make it out?

Answer 1

As shown in the Output, the declaration int x = 0 inside the for loop is not allowed with ANSI C. You will need to use C11 or C99.

Or you declare the integer outside of the for loop.

aE:

int x = 0; 
for(x; str[x] != '\0';x++){....