Why are there garbled characters in this C program output?-CodePudding

#include <stdio.h>
#include <locale.h>
#include <wchar.h>

int main() {
//    setlocale("LC_ALL","");
    unsigned char utf[]={0xe4,0xb8,0x80,0x0a};
    printf("%s",utf);
    return 0;
}

The first four bytes of output are correct. The second line in the console is not expected

CodePudding user response：

Your array is missing the null terminator strings require, so printf keeps on printing bytes beyond the end of the array until it happens upon a null byte. (Or when your program crashes due to an out of bounds access.)

Add the null byte:

unsigned char utf[]={0xe4,0xb8,0x80,0x0a,0x00};

CodePudding user response：

The format %s expects a pointer to a string as the corresponding argument. That is the sequence of outputted characters shall be ended with the terminating zero character '\0'.

This array

unsigned char utf[]={0xe4,0xb8,0x80,0x0a};

does not contain a string. So you need to specify explicitly how many characters you are going to output. For example

printf("%.*s", 4, utf);