Learn to Program with C_ Learn to Program using the Popular C Programming Language ( PDFDrive )

Chapter 3 ■ Programs with Sequence Logic
The first scanf will store 4000 in item. On completion, it remains poised at the space after
4000. The next scanf will continue reading from that point and will store 7.99 in price. This
scanf will stop at the space after 7.99. The third scanf will continue reading from that point
and store 8 in quantity. This scanf will stop at the character after 8; this may be a space or the
end-of-line character. Any subsequent scanf will continue reading from that point.
It is useful to imagine a “data pointer” moving through the data as data items are read. At any
time, it marks the position in the data from which the next scanf will start looking for the next
item of data.
3.4 Read Strings
In Section 2.6, we saw how to declare a variable to hold a string value. For example, the
declaration
char item[50];
lets us store a string value (of maximum length 49) in item. We also saw how we can assign a
string value to item using the standard string function, strcpy.
Now we show you how to read a value from the input into item. There are several ways to do
this in C. We will use the gets (usually pronounced get s not gets) statement (more precisely, a
function), as in:
gets(item);
This reads characters and stores them in item starting from the current position of the data
pointer until the end-of-line is reached. The end-of-line character is not stored. The data pointer
is positioned at the beginning of the next line.
For example, if the data line is
Right front headlamp
then the string Right front headlamp is stored in item. The effect is the same as if we had written
strcpy(item, "Right front headlamp");
The alert reader will notice that we did not put an & before item, as we have been doing for
reading numbers with scanf. For now, just note that item is a “character array” and the rule in C
is that we must not put & before an array name when reading data into it. You may understand
this better after we discuss arrays in Chapter 8. The quick explanation is that an array name
denotes the “address of the first element of the array” so there is no need for & to get the address.
For now, just think of it as a rule that you need to follow.
Consider the following statements (assume the declaration char name[50]):
printf("Hi, what's your name? ");
gets(name);
printf("Delighted to meet you, %s\n", name);
54
www.it-ebooks.info