字符串不会在C语言中自行打印

Question

I'm trying to format an ASCII-Art style string with strtok. When I try to run my program through my IDE it is actually printing my string which is in hexadecimal so I don't have to mess with all the backslashes in it. However when I try to run it in console (Ubuntu) it doesn't give anything back.

#include <sys/ioctl.h>
#include <stdio.h>
#include <string.h>

char pacmanText[] = { 0x20, 0x5f, 0x5f, 0x5f, 0x5f, 0x20, 0x20, 0x20, 0x20, 0x20, 
                      0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 
                      0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 
                      0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x0d, 
                      0x0a, 0x7c, 0x20, 0x20, 0x5f, 0x20, 0x5c, 0x20, 0x5f, 0x5f, 
                      0x20, 0x5f, 0x20, 0x20, 0x5f, 0x5f, 0x5f, 0x20, 0x5f, 0x20, 
                      0x5f, 0x5f, 0x20, 0x5f, 0x5f, 0x5f, 0x20, 0x20, 0x20, 0x5f, 
                      0x5f, 0x20, 0x5f, 0x20, 0x5f, 0x20, 0x5f, 0x5f, 0x20, 0x20, 
                      0x0d, 0x0a, 0x7c, 0x20, 0x7c, 0x5f, 0x29, 0x20, 0x2f, 0x20, 
                      0x5f, 0x60, 0x20, 0x7c, 0x2f, 0x20, 0x5f, 0x5f, 0x7c, 0x20, 
                      0x27, 0x5f, 0x20, 0x60, 0x20, 0x5f, 0x20, 0x5c, 0x20, 0x2f, 
                      0x20, 0x5f, 0x60, 0x20, 0x7c, 0x20, 0x27, 0x5f, 0x20, 0x5c, 
                      0x20, 0x0d, 0x0a, 0x7c, 0x20, 0x20, 0x5f, 0x5f, 0x2f, 0x20, 
                      0x28, 0x5f, 0x7c, 0x20, 0x7c, 0x20, 0x28, 0x5f, 0x5f, 0x7c, 
                      0x20, 0x7c, 0x20, 0x7c, 0x20, 0x7c, 0x20, 0x7c, 0x20, 0x7c, 
                      0x20, 0x28, 0x5f, 0x7c, 0x20, 0x7c, 0x20, 0x7c, 0x20, 0x7c, 
                      0x20, 0x7c, 0x0d, 0x0a, 0x7c, 0x5f, 0x7c, 0x20, 0x20, 0x20, 
                      0x5c, 0x5f, 0x5f, 0x2c, 0x5f, 0x7c, 0x5c, 0x5f, 0x5f, 0x5f, 
                      0x7c, 0x5f, 0x7c, 0x20, 0x7c, 0x5f, 0x7c, 0x20, 0x7c, 0x5f, 
                      0x7c, 0x5c, 0x5f, 0x5f, 0x2c, 0x5f, 0x7c, 0x5f, 0x7c, 0x20, 
                      0x7c, 0x5f, 0x7c, 0x0d, 0x0a
}; 

int main() 
{ 
    struct winsize w; 
    ioctl(0, TIOCGWINSZ, &w); 

    char *pch = NULL; 

    pch = strtok(pacmanText, "\n"); 
    while (pch != NULL) 
    { 
        printf("%s", pch); 
        fflush(stdout); 

        pch = strtok(NULL, "\n"); 

    } 
    return 0; 
}

So can anyone tell me why it won't print me that string?

Answer 1

There is no '\\0' terminator in your string, just add one more element to the array at it's end 0x00 , also your strtok() is splitting the lines properly, the problem is you miss the '\\n' character at the end of the line, so just change this

printf("%s", pch);

to

printf("%s\n", pch);

but, there is no point in doing that. You can just use printf("%s", pacmanText);

So the fundamental problem is strtok() it replaces the delimiter with '\\0' so when you do this

printf("%s", pch);

you are not printing the delimiter.

Answer 2

Issues:

1. You need a null terminating character at the end of pacmanText for the reasons that iharob talks about .
2. strtok() will modify the string such that the separator character is replaced by a '\\0' . So you never print a newline in the entire program.

Let's fix these bugs:

#include <stdio.h>
#include <string.h>

char pacmanText[] = {
    0x20, 0x5f, 0x5f, 0x5f, 0x5f, 0x20, 0x20, 0x20, 0x20, 0x20, 
    0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 
    0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 
    0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x0d, 
    0x0a, 0x7c, 0x20, 0x20, 0x5f, 0x20, 0x5c, 0x20, 0x5f, 0x5f, 
    0x20, 0x5f, 0x20, 0x20, 0x5f, 0x5f, 0x5f, 0x20, 0x5f, 0x20, 
    0x5f, 0x5f, 0x20, 0x5f, 0x5f, 0x5f, 0x20, 0x20, 0x20, 0x5f, 
    0x5f, 0x20, 0x5f, 0x20, 0x5f, 0x20, 0x5f, 0x5f, 0x20, 0x20, 
    0x0d, 0x0a, 0x7c, 0x20, 0x7c, 0x5f, 0x29, 0x20, 0x2f, 0x20, 
    0x5f, 0x60, 0x20, 0x7c, 0x2f, 0x20, 0x5f, 0x5f, 0x7c, 0x20, 
    0x27, 0x5f, 0x20, 0x60, 0x20, 0x5f, 0x20, 0x5c, 0x20, 0x2f, 
    0x20, 0x5f, 0x60, 0x20, 0x7c, 0x20, 0x27, 0x5f, 0x20, 0x5c, 
    0x20, 0x0d, 0x0a, 0x7c, 0x20, 0x20, 0x5f, 0x5f, 0x2f, 0x20, 
    0x28, 0x5f, 0x7c, 0x20, 0x7c, 0x20, 0x28, 0x5f, 0x5f, 0x7c, 
    0x20, 0x7c, 0x20, 0x7c, 0x20, 0x7c, 0x20, 0x7c, 0x20, 0x7c, 
    0x20, 0x28, 0x5f, 0x7c, 0x20, 0x7c, 0x20, 0x7c, 0x20, 0x7c, 
    0x20, 0x7c, 0x0d, 0x0a, 0x7c, 0x5f, 0x7c, 0x20, 0x20, 0x20, 
    0x5c, 0x5f, 0x5f, 0x2c, 0x5f, 0x7c, 0x5c, 0x5f, 0x5f, 0x5f, 
    0x7c, 0x5f, 0x7c, 0x20, 0x7c, 0x5f, 0x7c, 0x20, 0x7c, 0x5f, 
    0x7c, 0x5c, 0x5f, 0x5f, 0x2c, 0x5f, 0x7c, 0x5f, 0x7c, 0x20, 
    0x7c, 0x5f, 0x7c, 0x0d, 0x0a, 0x00
}; 

int main() { 
    char *pch = strtok(pacmanText, "\n"); 
    while (pch != NULL) { 
        printf("%s\n", pch); 
        pch = strtok(NULL, "\n"); 
    } 
}

Which outputs:

[1:08pm][wlynch@watermelon /tmp] ./foo
 ____                                  
|  _ \ __ _  ___ _ __ ___   __ _ _ __  
| |_) / _` |/ __| '_ ` _ \ / _` | '_ \ 
|  __/ (_| | (__| | | | | | (_| | | | |
|_|   \__,_|\___|_| |_| |_|\__,_|_| |_|