int putchar(int char); 

put a character into stdout

/* 
 * putchar example code
 * http://code-reference.com/c/stdio.h/putchar
 */
 
#include <stdio.h> /* including standard library */
//#include <windows.h> /* uncomment this for Windows */
 
 
int main( void )
{
  int c;
  c = 0; // ASCII Code a
 
  while (c < 255) { // count chars in a while loop
     putchar(c);
     c++;
  }
 
  putchar('\n');
  return 0;
}

output complete ASCII Table

   ./putchar 
  
  
   
  123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~????????????????????????????????????????????????????????????????????????????????????????????????