The difference between gets and scanf

Source: Internet
Author: User

scanf and gets read the string

Learn more about functions such as scanf ()/getchar () and gets ()

scanf the difference between reading a string with the Gets function

See a paragraph today, roughly say get than scanf () quick, a little surprised, searched, scanf () and gets the difference roughly have a few:

1.SCANF () ignores all whitespace at the beginning of the line and ends the input with a space and line break;

After the SCANF statement is executed using GetChar (), the buffer leaves a newline character,

The get reads a string that starts with any character, ends with a newline, but then discards the newline character and replaces it with a ' + ';

2. in the case of large numbers of data, with get read faster than scanf () more than 10 times times (note: From the PUDN, only a paragraph of the opening words)

3.

First: pay attention to whether the different functions accept whitespace, whether to discard the last carriage return problem!
When reading characters:
scanf () ends the input with space, enter, tab, and does not discard the last carriage return (that is, the carriage return remains in the buffer);
GetChar () ends the input with enter and does not discard the last carriage return;
When reading a string:
scanf () end one input with space, enter, tab
Gets () ends the input with enter (the space does not end), accepts the space, discards the last carriage return!

Second: in order to avoid this problem, you must clear the buffer residual data, can be resolved by the following methods:
The 1:c method provides a function to empty the buffer in the language, so long as the buffer is emptied before reading the data, no problem!
This function is Fflush (stdin).
Method 2: Remove the residual data from the buffer itself.
(To tell the truth this statement I did not read, hehe!) Why is the format control like this! I hope the expert pointed out! )
scanf ("%[^\n]", string);

Experiment code: Word solitaire, enter n and n words to determine if the words are the same

#include <iostream>#include<string.h>using namespacestd;intMain () {intN; Charword_pre[ One]; Charword[ One]; BOOLIsNo =false;  while(SCANF ("%d", &n)! =EOF) {        //fflush (stdin);GetChar (); IsNo=false;  for(intI=0; i<n;i++)        {            if(i = =0)                //scanf ("%s", word_pre);gets (Word_pre); Else            {                //scanf ("%s", word);gets (word); if(Word_pre[strlen (Word_pre)-1] = = word[0]) {strcpy (Word_pre,word); }                Else{isNo=true;  Break; }            }        }        if(isNo) printf ("no\n"); Elseprintf"yes\n"); }    return 0;}

Language C C + Pascal
to read numbers int n;
while (scanf ("%d", &n)! = EOF)
{
...
}
int n;
while (CIN >> N)
{
...
}
var N:integer;
...  
While not seekeof do
begin
Read (n);
...
End;
to read characters int c;
while ((c = GetChar ())! = EOF)
{
...
}
char c;
while (Cin.get (c))
{
...
}
var C:char;
...
While not EOF do
begin
Read (c);  
...
End;
to read lines char line[1024];
while (gets)
{
...
}
string line;
while (Getline (CIN, line))
{
...
}
var line:string;
...  
While not EOF does
begin
Readln (line);
...
End;

Gets and scanf differences

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