问题
#include <stdio.h>
#define MAX_STRING_LENGTH 1024
int main(){
char input_name_string[MAX_STRING_LENGTH+1],motive_string[MAX_STRING_LENGTH+1];
printf("What is your name?\n");
scanf("%1024s",input_name_string);
printf("your name is %s \n", input_name_string);
printf("What is your motive?\n");
scanf(" %1024s",motive_string);
printf("your motive is %s \n", motive_string);
return 0; }
So I wrote this simple program for a project in school to try and learn how scanf and printf work. For some reason when this runs it prints the first word in each string on one line then the second word on another line. I don't understand why this is happening? I don't have experience in C but the logic in my code seems correct? Any suggestions
回答1:
The function scanf with the conversion format specifier used by you reads characters until a white space character is encountered.
Instead use the function fgets.
For example
fgets( input_name_string, sizeof( input_name_string ), stdin );
The function can append also the new line character to the entered string. To remove it you can write
#include <string.h>
/ …
input_name_string[ strcspn( input_name_string, "\n" ) ] = '\0';
As for you format specifier
scanf("%1024s",input_name_string);
than in any case it is incorrect. Instead of 1024 as the field width should be one less than the size of the character array to reserve one character for the terminating zero character '\0'.
You could write
scanf( "%1023[^\n]\n", input_name_string );
来源：https://stackoverflow.com/questions/59883621/why-does-my-code-keep-printing-twice-i-dont-understand-the-problem