Data commit

Task/Totient-function/C/totient-function.c

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+/*Abhishek Ghosh, 7th December 2018*/
+
+#include<stdio.h>
+
+int totient(int n){
+	int tot = n,i;
+	
+	for(i=2;i*i<=n;i+=2){
+		if(n%i==0){
+			while(n%i==0)
+				n/=i;
+			tot-=tot/i;
+		}
+		
+		if(i==2)
+			i=1;
+	}
+	
+	if(n>1)
+		tot-=tot/n;
+	
+	return tot;
+}
+
+int main()
+{
+	int count = 0,n,tot;
+	
+	printf(" n    %c   prime",237);
+        printf("\n---------------\n");
+	
+	for(n=1;n<=25;n++){
+		tot = totient(n);
+		
+		if(n-1 == tot)
+			count++;
+		
+		printf("%2d   %2d   %s\n", n, tot, n-1 == tot?"True":"False");
+	}
+	
+	printf("\nNumber of primes up to %6d =%4d\n", 25,count);
+	
+	for(n = 26; n <= 100000; n++){
+        tot = totient(n);
+        if(tot == n-1)
+			count++;
+
+        if(n == 100 || n == 1000 || n%10000 == 0){
+            printf("\nNumber of primes up to %6d = %4d\n", n, count);
+        }
+    }
+	
+	return 0;
+}