Scanf 和 printf 一个包含两个单词的字符串

Question

I want to make a program to output a string that includes two words using scanf and printf functions.

This is my source code:

#include <stdio.h>
int main () 
{
    char str[20];
    scanf("%s%s", &str);
    printf("%s", str);
    return 0;
}

After I run the code the results are not what I want.

Input:

new version

Output:

new

What is the solution for this problem?

Answer 1

You can read an entire string including spaces using [^\\n] specifier, which means read everything in the input stream until a newline character is found.

#include <stdio.h>
int main () 
{
    char str[100]; //20 characters is not much, addded a little more
    scanf("%99[^\n]", str); //size limit 99 + null byte
    printf("%s", str);
    return 0;
}

Note that operator & is not needed for char arrays in scanf and the input should be limited to the size of the destination buffer to avoid buffer overflow.

A character is 1 byte, in today's machines, generally speaking, that amounts to almost nothing, so be more generous with your char arrays if you can.