c语言补充内容.ppt

C语言补充内容;内容;内容;命令行参数;命令行参数（2）;/* Fig. 14.3: fig14_03.c Using command-line arguments */ #include stdio.h int main( int argc, char *argv[] ) { FILE *inFilePtr; /* input file pointer */ FILE *outFilePtr; /* output file pointer */ int c; /* define c to hold characters input by user */ /* check number of command-line arguments */ if ( argc != 3 ) { printf( Usage: mycopy infile outfile\n ); } /* end if */ else { /* if input file can be opened */ if ( ( inFilePtr = fopen( argv[ 1 ], r ) ) != NULL ) { /* if output file can be opened */ if ( ( outFilePtr = fopen( argv[ 2 ], w ) ) != NULL ) { ; /* read and output characters */ while ( ( c = fgetc( inFilePtr ) ) != EOF ) { fputc( c, outFilePtr ); } /* end while */ } /* end if */ else { /* output file could not be opened */ printf( File \%s\ could not be opened\n, argv[ 2 ] ); } /* end else */ } /* end if */ else { /* input file could not be opened */ printf( File \%s\ could not be opened\n, argv[ 1 ] ); } /* end else */ } /* end else */ return 0; /* indicates successful termination */ } /* end main */;内容;可变长的实参列表;/* Fig. 14.2: fig14_02.c Using variable-length argument lists */ #include stdio.h #include stdarg.h double average( int i, ... ); /* prototype */ int main( void ) { double w = 37.5; double x = 22.5; double y = 1.7; double z = 10.2; printf( %s%.1f\n%s%.1f\n%s%.1f\n%s%.1f\n\n, w = , w, x = , x, y = , y, z = , z ); printf( %s%.3f\n%s%.3f\n%s%.3f\n, The average of w and x is , average( 2, w, x ), The average of w, x, and y is , average( 3, w, x, y ), The average of w, x, y, and z is , average( 4, w, x, y, z ) ); return 0; /* indicates successful termination */ } /* end main */; /* calculate average */ double average( int i, ... ) { double total = 0; /* initialize total */ in