字符串和字符串函数
conception: 字符串是以空字符（\0）结尾的char类型数组。
程序中定义字符串
// Two solutions
// 1.pointer define
const char *pt = "this is a string";
// 2.array define
char arr[] = "this is a string";
char arr[20] = "this is a string";
// Following is the distinction of two solution:
// the first solution: pointer point original string in the static memory
// the first solution: pointer can't change value of the string
// the second solution: the array is the copy from original string in the static memory
// the second solution: value of array can be changed
字符串输入与输出
// common input and output function
// gets() is deprecated
char words[10];
gets(words); // Read 9 character and add a new line character
// puts()
puts("hello, world!"); // Print string and add a new line character
// fgets()
#define STLEN 10
char words[STLEN];
fgets(words, STLEN, stdin); // stdin means you want to accept input from keyboard
// fgets will read new line symbol as a character
// fputs()
fputs(words, stdout); // stdout means you want to output on the screen, it will not add a new line character
// gets_s()
#define STLEN 10
char words[STLEN];
gets_s(words, STLEN); // gets_s() only read data from stdin, it will not accept new line symbol like fgets()
// scanf()
// printf()
- Following is encapsulation of
fgets()
char * s_gets(char * st, int n)
{
char * ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}