Print all prefixes?

#include<iostream>
using namespace std ;

void print_all_prefixes(char str[]){

    for (int i = 0; str[i] != '\0'; ++i) {
        for (int j = 0; j <= i ; ++j) {
            cout << str[j] ;
        }
        cout << '\n' ;
    }
}

int main(){
    char str[] = "abcd" ; 
    print_all_prefixes(str) ;


    return 0 ;
}