asked on

how to check the input data

#include <stdio.h>
#include <ctype.h>
#include <string.h>

void main() {

char mid,month[3];
int day, i, mon=0;
printf("Enter a date in the format (dd-MMM): ");
scanf("%d - %s", &day, &month);
if(day==' ' || day=='\0' )
printf("Error: Nothing is Entered.");
else {
for(i=0;i<3;i++)
month[i]=toupper(month[i]);

if(strcmp(month, "JAN")==0)
mon=1;
if(strcmp(month, "FEB")==0)
mon=2;
if(strcmp(month, "MAR")==0)
mon=3;
if(strcmp(month, "APR")==0)
mon=4;
if(strcmp(month, "MAY")==0)
mon=5;
if(strcmp(month, "JUN")==0)
mon=6;
if(strcmp(month, "JUL")==0)
mon=7;
if(strcmp(month, "AUG")==0)
mon=8;
if(strcmp(month, "SEP")==0)
mon=9;
if(strcmp(month, "OCT")==0)
mon=10;
if(strcmp(month, "NOV")==0)
mon=11;
if(strcmp(month, "DEC")==0)
mon=12;

printf("Day entered: %d\n", day);
printf("Month entered: %s\n", month);
printf("Month entered: %d\n", mon);
}
}

If nothing or just spaces are entered, the program should print the following
message: Nothing is Entered.
If the entered string does not match the dd-MMM format, the following message
should be printed: Invalid Format.
• If the entered month does not match any one of the 12 abbreviated month labels,
the following message should be printed: Unrecognized Month.
• If the entered day and month values do not appear in a calendar of normal year
(non-leap year), the following message should be printed: Invalid Date.

Jaime Olivares

Looks like a homework, maybe you can start posting some try.

ASKER CERTIFIED SOLUTION

Kent Olsen

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PaulCaswell

Hint:

1. Lookup what scanf returns.

2. Lookup what scanf does if parameters are not there or spaces.

Paul

carothy

ASKER

Paul:

could give me any reference about what scanf does if parameters are not there or spaces.

and can i modify as follow:

#include <stdio.h>
#include <ctype.h>
#include <string.h>

void main() {

char month[4];
int day, i, mon=0;
printf("Enter a date in the format (dd-MMM): ");
i=scanf("%d - %s", &day, &month);
if(i!=0 )
printf("Error: Nothing is Entered.");
else {
for(i=0;i<3;i++)
month[i]=toupper(month[i]);

if(strcmp(month, "JAN")==0)
mon=1;
if(strcmp(month, "FEB")==0)
mon=2;
if(strcmp(month, "MAR")==0)
mon=3;
if(strcmp(month, "APR")==0)
mon=4;
if(strcmp(month, "MAY")==0)
mon=5;
if(strcmp(month, "JUN")==0)
mon=6;
if(strcmp(month, "JUL")==0)
mon=7;
if(strcmp(month, "AUG")==0)
mon=8;
if(strcmp(month, "SEP")==0)
mon=9;
if(strcmp(month, "OCT")==0)
mon=10;
if(strcmp(month, "NOV")==0)
mon=11;
if(strcmp(month, "DEC")==0)
mon=12;

printf("Day entered: %d\n", day);
printf("Month entered: %s\n", month);
}
}

Kent Olsen

Hi Carothy,

I suggest that your format string look more like this:

i=scanf("%d - %3s", &day, &month);

Otherwise you still run the rist of a buffer overflow. :(

Kent

SOLUTION

PaulCaswell

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Kent Olsen

>> i=scanf("%d - %3s", &day, &month);
This will crash. I'd suggest instead:
i=scanf("%d - %3s", &day, month);

Whoops. :)

Although most compilers detect the "superfluous &' and issue a warning. Many even ignore it. Still, I should have caught it.

Kent