getting errors on simple awk script for-in declaration - bash

Question

I wrote a simple awk function to print every characters in a array and the compiler is returning the following errors and I don't know what could be wrong.
function print_streaks_info(arr) {
for(index in arr){
print "starting index: " index
}
}
awk: streak_script.awk: line 2: syntax error at or near in
awk: streak_script.awk: line 5: syntax error at or near }
I didn't try much since i am just starting out with awk and the code is copied and pasted from a tutorial

Answer 1

As mark-fuso stated in the comments, the issue is your use of the reserved word "index", which is a built-in function for searching for patterns in a string.
If you replace your script instances of "index" by "indx", your script will work without problems.
Below is a demo script incorporating your original function (modified) and using Carlo Costa's test array (also modified):
#!/bin/bash
echo "" |
awk '\
function print_streaks_info(arr){
for( indx in arr ){
print "starting index: " indx ;
break ;
} ;
}
BEGIN{
Customer["14587"] = "Neil Johnson" ;
Customer["8953"] = "Ella binte Nazir" ;
Customer["23455"] = "Bruce Hyslop" ;
Customer["6335"] = "Isabella" ;
}
END{
print_streaks_info(Customer) ;
}'
echo -e "\n NOTE: The 'in' operator is reporting the array in sequential order of the indexes,\n\t NOT in the order in which they were assigned.\n"