最初に設定string[0]
してみてください\0
。また、null で終了するbuffer
必要があります。char *
ページからman
:
NAME
strcat, strncat -- concatenate strings
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <string.h>
char *
strcat(char *restrict s1, const char *restrict s2);
char *
strncat(char *restrict s1, const char *restrict s2, size_t n);
DESCRIPTION
The strcat() and strncat() functions append a copy of the null-terminated
string s2 to the end of the null-terminated string s1, then add a termi-
nating `\0'. The string s1 must have sufficient space to hold the
result.