Palindromic primes: Difference between revisions

Content added Content deleted

Inline

@@ Line 6: / Line 6: @@
 <br><br>
+=={{header|AWK}}==
+<lang AWK>
+# syntax: GAWK -f PALINDROMIC_PRIMES.AWK
+BEGIN {
+    start = 1
+    stop = 999
+    for (i=start; i<=stop; i++) {
+      if (is_prime(i) && reverse(i) == i) {
+        printf("%d ",i)
+        count++
+      }
+    }
+    printf("\nPalindromic 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 reverse(str,  i,rts) {
+    for (i=length(str); i>=1; i--) {
+      rts = rts substr(str,i,1)
+    }
+    return(rts)
+}
+</lang>
+{{out}}
+<pre>
+3 5 7 11 101 131 151 181 191 313 353 373 383 727 757 787 797 919 929
+Palindromic primes 1-999: 20
+</pre>
 =={{header|Factor}}==
 ===Simple===