C语言 如何检查用户是否按下了 Enter 键？
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时间：2020-09-02 07:55:11 来源:igfitidea点击:
How to check if user pressed Enter key ?
提问by Barbiyong
#include <stdio.h>
#include <string.h>
#include "formatCheck.h"
int main()
{
char input[32];
char format[32]
printf("enter your format : ");
fgets(input,sizeof(input),stdin);
sscanf(input,"%s",format);
//my problem
//if user don't enter format it will exit.
if()
{
return 0;
}
}
How can I check if user doesn't input anything (just Enter key). Sorry about English. Thanks.
如何检查用户是否未输入任何内容（只需 Enter 键）。对不起英语。谢谢。
回答by niko
When user hits only enter, input[0] contains \n
当用户点击仅进入时， input[0] contains \n
fgets(input,sizeof(input),stdin);
if(input[0]=='\n') printf("empty string");
回答by Some programmer dude
回答by awesum
you can check if the length of input text is 0 or NULL.
您可以检查输入文本的长度是 0 还是NULL.
回答by Sahil Sareen
/* fgets example */
#include <stdio.h>
int main()
{
FILE * pFile;
char mystring [100];
pFile = fopen ("myfile.txt" , "r");
if (pFile == NULL) perror ("Error opening file");
else {
if ( fgets (mystring , 100 , pFile) != NULL ) //Use this
puts (mystring);
fclose (pFile);
}
return 0;
}
/* fgets example 2 */
#include <stdio.h>
int main()
{
FILE * pFile;
char mystring [100];
pFile = fopen ("myfile.txt" , "r");
if (pFile == NULL) perror ("Error opening file");
else {
if ( fgets (mystring , 100 , pFile) && input[0]!='\n' ) //Use this
puts (mystring);
fclose (pFile);
}
return 0;
}
Reference : http://www.cplusplus.com/reference/cstdio/fgets/
