program
#include <stdio.h>
main()
{
    /* variable declarations */
    int a, b, c; Trace
    /* calculations */ a   b    c
    a = 3; 3  ---  ---
    b = 2 * a; 3   6   ---
    c = b * b; 3   6    36
    a = a + b; 9   6    36
    /* print variables' values */
    printf("a, b, and c are %d, %d, and %d\n”, a, b, c);
    printf("%d\n", 2 * a); 
    return 0;
}
output:
a, b, and c are 9, 6, 36
18