в 14:21, 25 мая 2010

2010-05-25T14:21:19Z

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2010-05-25T10:32:36Z

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==Pass pointer argument to scanf==

<source lang="cpp">#include <stdio.h>
int main(void)
{
int value = 0;
int *pvalue = NULL;
pvalue = &value; /* Set pointer to refer to value */
printf ("Input an integer: ");
scanf(" %d", pvalue); /* Read into value via the pointer */
printf("\nYou entered %d\n", value);
return 0;
}</source>
<pre class=codeResult>Input an integer: string

You entered 0</pre>

==Reading and discarding characters from the input stream==

<source lang="cpp">#include <stdio.h>
int main()
{
int month1;
int day1;
int year1;
int month2;
int day2;
int year2;

printf( "Enter a date in the form mm-dd-yyyy: " );
scanf( "%d%*c%d%*c%d", &month1, &day1, &year1 );
printf( "month = %d day = %d year = %d\n\n", month1, day1, year1 );

printf( "Enter a date in the form mm/dd/yyyy: " );
scanf( "%d%*c%d%*c%d", &month2, &day2, &year2 );

printf( "month = %d day = %d year = %d\n", month2, day2, year2 );
return 0;
}</source>
<pre class=codeResult>Enter a date in the form mm-dd-yyyy: 01-01-2001
month = 1 day = 1 year = 2001
Enter a date in the form mm/dd/yyyy: 01/01/2002
month = 1 day = 1 year = 2002</pre>

==scanf==

The scanf function: read information from a standard input device (keyboard).

<source lang="cpp">scanf("conversion specifier", variable);</source>
The conversion specifier argument tells scanf how to convert the incoming data.
<OL><LI>scanf starts with a string argument and may contain additional arguments.</LI><LI>Additional arguments must be pointers.</LI><LI>scanf returns the number of successful inputs.</LI></OL>
Common Conversion Specifiers Used with Scanf
Conversion Specifier
Description
%d
Receives integer value
%f
Receives floating-point numbers
%c
Receives character

==The scanf placeholders==

d, i Used for signed integers; the expected argument should be a pointer to int.

<source lang="cpp">#include <stdio.h>
main()
{
int i = 0;
int k;
printf("input an integer:\n");
i=scanf("%d",&k);
printf("total values inputted %d\n",i);
printf("The input values %d\n",k);
}</source>
<pre class=codeResult>input an integer:
3
total values inputted 1
The input values 3</pre>

==Use scanf to get input from a standard input device, such as a keyboard==

In scanf, you have to specify the address of a variable, such as &i, &j, and a list of format specifiers (%d).
The number of format specifiers must be the same as the number of variables.

<source lang="cpp">#include <stdio.h>
main(){
int i,j,k;
printf("Input two integers and press Enter to comfirm:");
scanf("%d%d",&i,&j);
k = i + j;
printf("sum of two numbers is %d \n",k);
}</source>
<pre class=codeResult>Input two integers and press Enter to comfirm:223
2
sum of two numbers is 225</pre>

==Using an inverted scan set==

<source lang="cpp">#include <stdio.h>
int main()
{
char z[ 9 ];

printf( "Enter a string: " );
scanf( "%[^aeiou]", z );
printf( "The input was \"%s\"\n", z );
return 0;
}</source>
<pre class=codeResult>Enter a string: string
The input was "str"</pre>

==Using Scanf to Receive Input from a User==

<source lang="cpp">#include <stdio.h>
main(){
int iOperand1 = 0;
int iOperand2 = 0;
printf("\nEnter first operand: ");
scanf("%d", &iOperand1);
printf("Enter second operand: ");
scanf("%d", &iOperand2);
printf("The result is %d\n", iOperand1+iOperand2);
}</source>
<pre class=codeResult>Enter first operand: 1
Enter second operand: 2
The result is 3</pre>

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в 14:21, 25 мая 2010

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