Data commit

Task/Additive-primes/AWK/additive-primes.awk

@@ -0,0 +1,29 @@
+# syntax: GAWK -f ADDITIVE_PRIMES.AWK
+BEGIN {
+    start = 1
+    stop = 500
+    for (i=start; i<=stop; i++) {
+      if (is_prime(i) && is_prime(sum_digits(i))) {
+        printf("%4d%1s",i,++count%10?"":"\n")
+      }
+    }
+    printf("\nAdditive primes %d-%d: %d\n",start,stop,count)
+    exit(0)
+}
+function is_prime(x,  i) {
+    if (x <= 1) {
+      return(0)
+    }
+    for (i=2; i<=int(sqrt(x)); i++) {
+      if (x % i == 0) {
+        return(0)
+      }
+    }
+    return(1)
+}
+function sum_digits(n,  i,sum) {
+    for (i=1; i<=length(n); i++) {
+      sum += substr(n,i,1)
+    }
+    return(sum)
+}