Sams Teach Yourself C in 21 Days

In Review 621

CH 21 43: if( argc < 2 )

44: {

45: display_usage(“WEEK3”);

46: exit(1);

47: }

48:

49: /* Open file. */

CH 16 50: if ((fp = fopen( argv[1], “a+”)) == NULL)

51: {

52: fprintf( stderr, “%s(%d)—Error opening file %s”,

53: argv[0],__LINE__, argv[1]);

54: exit(1);

55: }

56:

57: while( cont == YES )

58: {

59: switch( display_menu() )

60: {

CH 18 61: case ‘1’: get_data(fp, argv[0], argv[1]); /* Day 18*/

62: break;

63: case ‘2’: display_report(fp);

64: break;

65: case ‘3’: look_up(fp);

66: break;

67: case ‘4’: printf(“\n\nThank you for using this program!\n”);

68: cont = NO;

69: break;

70: default: printf(“\n\nInvalid choice, Please select 1 to 4!”);

71: break;

72: }

73: }

CH 16 74: fclose(fp); /* close file */

75: return(0);

76: }

77:

78: /* display_menu() */

79:

80: int display_menu(void)

81: {

82: char ch, buf[20];

83:

84: printf( “\n”);

85: printf( “\n MENU”);

86: printf( “\n ========\n”);

87: printf( “\n1. Enter names”);

88: printf( “\n2. Print report”);

89: printf( “\n3. Look up number”);

90: printf( “\n4. Quit”);

91: printf( “\n\nEnter Selection ==> “);

92: gets(buf);

93: ch = *buf;

LISTINGR3.1 continued

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