程序代码：

#include <stdio.h>

int main( void )
{
    const double a = 12.3456;
    const char* b = "program";

    printf( "%.2f\n", a );
    printf( "%10.6f\n", a );
    printf( "%.0f\n", a );

    printf( "%10s\n", b );
    printf( "%10.4s\n", b );
    printf( "%.3s\n", b );
}