book@100ask:~/C_coding/CH01$ cat char1.c
#include <stdio.h>
#include <stdlib.h>
#define N 32
int main()
{
char str[N] = {'a','b','c'};
int i;
scanf("%s",str);
printf("%s\n",str);
exit(0);
}
book@100ask:~/C_coding/CH01$ make char1
cc char1.c -o char1
book@100ask:~/C_coding/CH01$ ./char1
hello
hello
book@100ask:~/C_coding/CH01$
book@100ask:~/C_coding/CH01$ cat char1.c
#include <stdio.h>
#include <stdlib.h>
#define N 32
int main()
{
char str[N],str1[N],str2[N];
int i;
scanf("%s%s%s",str,str1,str2);
printf("%s\n%s\n%s\n",str,str1,str2);
exit(0);
}
book@100ask:~/C_coding/CH01$ make char1
cc char1.c -o char1
book@100ask:~/C_coding/CH01$ ./char1
hello word chaina
hello
word
chaina
book@100ask:~/C_coding/CH01$ ./char1
hello he2 he3 he4 he5 he6 //當有多個輸出時，自動只賦值前三個串
hello
he2
he3
字符串常用函數：
strlen & sizeof
book@100ask:~/C_coding/CH01$ cat char2.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// strlen & sizeof
#define N 32
int main()
{
char str[] = "hello";
printf("%d\n",strlen(str)); //strlen顯示字符的實際長度，此處hello包含5個字符，故顯示5
printf("%d\n",sizeof(str)); //sizeof打印字符串的總長度，包括尾零，此處hello包括尾零共6
exit(0);
}
book@100ask:~/C_coding/CH01$ make char2
cc char2.c -o char2
book@100ask:~/C_coding/CH01$ ./char2
5
6
book@100ask:~/C_coding/CH01$ cat char2.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 32
int main()
{
char str[] = "hello\0abc";
printf("%d\n",strlen(str)); //strlen以\0分割，因此此處打印5
printf("%d\n",sizeof(str)); //sizeof會將中間的\0也算進去，算一個空間，hello + \0 + abc + \0 = 10個字符空間
exit(0);
}
book@100ask:~/C_coding/CH01$ ./char2
5
10
strcpy & strncpy
book@100ask:~/C_coding/CH01$ cat strcp.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 32
int main()
{
char str[] = "hello\0abc"; //給字符串數組str賦初值
strcpy(str,"abcde"); //將abcde copy給字符串數組str
puts(str); //將strcp運算後的字符串str輸出
exit(0);
}
book@100ask:~/C_coding/CH01$ make strcp
cc strcp.c -o strcp
book@100ask:~/C_coding/CH01$ ./strcp
abcde
book@100ask:~/C_coding/CH01$ cat strcp.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 32
int main()
{
char str[3]; //初始化，定義字符串數組的長度爲3
strcpy(str,"abcde"); //當copy的內容超過容量，仍然可以賦值，即字符串數組長度的定義在此處失效
puts(str);
exit(0);
}
book@100ask:~/C_coding/CH01$ make strcp
cc strcp.c -o strcp
book@100ask:~/C_coding/CH01$ ./strcp
abcde
book@100ask:~/C_coding/CH01$ cat strncp.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define STRSIZE 32
int main()
{
char str[STRSIZE];
strncpy(str,"abcde",STRSIZE); //限定copy的最大字符數爲STRSIZE
puts(str);
exit(0);
}
book@100ask:~/C_coding/CH01$ make strncp
cc strncp.c -o strncp
book@100ask:~/C_coding/CH01$ ./strncp
abcde
book@100ask:~/C_coding/CH01$ cat strncp.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define STRSIZE 3
int main()
{
char str[STRSIZE];
strncpy(str,"abcde",STRSIZE); //當限定copy的最大字符數爲STRSIZE=3時，最多可被copy3個字符
puts(str);
exit(0);
}
book@100ask:~/C_coding/CH01$ make strncp
cc strncp.c -o strncp
book@100ask:~/C_coding/CH01$ ./strncp
abc
strcat & strncat
book@100ask:~/C_coding/CH01$ cat strcat.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define STRSIZE 32
int main()
{
char str[STRSIZE] = "hello";
strcat(str," "); //strcat負責把不同的字符串連接在一起
strcat(str,"world!");
puts(str);
exit(0);
}
book@100ask:~/C_coding/CH01$ make strcat
cc strcat.c -o strcat
book@100ask:~/C_coding/CH01$ ./strcat
hello world!
book@100ask:~/C_coding/CH01$ cat strnc
strncat strncat.c strncp strncp.c
book@100ask:~/C_coding/CH01$ cat strncat.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define STRSIZE 5
int main()
{
char str[STRSIZE] = "hello";
strncat(str," ",STRSIZE);
strncat(str,"world!",STRSIZE); //限定一次連接的最大長度爲STRSIZE
puts(str);
exit(0);
}
book@100ask:~/C_coding/CH01$ make strncat
cc strncat.c -o strncat
book@100ask:~/C_coding/CH01$ ./strncat
hello world
strcmp & strncmp
book@100ask:~/C_coding/CH01$ cat strcmp.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define STRSIZE 32
int main()
{
char str[STRSIZE] = "hello";
char str1[STRSIZE] = "world";
printf("%d\n",strcmp(str,str1)); //對比，左邊的字符串（從第一個字符開始比較，大於則返回整數，小於返回負數）
exit(0);
}
book@100ask:~/C_coding/CH01$ make strcmp
cc strcmp.c -o strcmp
book@100ask:~/C_coding/CH01$ ./strcmp
-15
book@100ask:~/C_coding/CH01$ cat strcmp.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define STRSIZE 32
int main()
{
char str[STRSIZE] = "hello";
char str1[STRSIZE] = "aworld";
printf("%d\n",strcmp(str,str1));
exit(0);
}
book@100ask:~/C_coding/CH01$ make strcmp
cc strcmp.c -o strcmp
book@100ask:~/C_coding/CH01$ ./strcmp
7
book@100ask:~/C_coding/CH01$ cat strcmp.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define STRSIZE 32
int main()
{
char str[STRSIZE] = "hello";
char str1[STRSIZE] = "hello";
printf("%d\n",strcmp(str,str1));
exit(0);
}
book@100ask:~/C_coding/CH01$ make strcmp
cc strcmp.c -o strcmp
book@100ask:~/C_coding/CH01$ ./strcmp
0
book@100ask:~/C_coding/CH01$ cat strcmp.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define STRSIZE 32
int main()
{
char str[STRSIZE] = "hello";
char str1[STRSIZE] = "helloa";
printf("%d\n",strcmp(str,str1));
exit(0);
}
book@100ask:~/C_coding/CH01$ make strcmp
cc strcmp.c -o strcmp
book@100ask:~/C_coding/CH01$ ./strcmp
-97
book@100ask:~/C_coding/CH01$ cat strncmp.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define STRSIZE 32
int main()
{
char str[STRSIZE] = "hello";
char str1[STRSIZE] = "helloa";
printf("%d\n",strncmp(str,str1,5)); //strncmp設定對比的字符數爲前n個
exit(0);
}
book@100ask:~/C_coding/CH01$ make strncmp
cc strncmp.c -o strncmp
book@100ask:~/C_coding/CH01$ ./strncmp
0