C Code13

#include <stdio.h>
#include <string>
char c[30];
char n[30];
int main(int argc, char** argv)
{
printf("Enter code: ");
scanf("%s", c);
for(int i=0;i<strlen(c);i++)
{
if (c[i] >= 48 && c[i] <= 57)
n[i] = ((c[i] - 48 + 13) % 10) + 48;
if(c[i]>=65 && c[i]<=90)
n[i] = ((c[i] - 65 + 13) % 26) + 65;
if(c[i] >= 97 && c[i] <= 122)
n[i] = ((c[i] - 97 + 13) % 26) + 97;
printf("%c", n[i]);
}
printf("\n");
return 0;
}