C语言 如何访问字符数组的第一个字符？
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How to access the first character of a character array?
提问by Kay
#include <stdio.h>
int main(void){
char x [] = "hello world.";
printf("%s \n", &x[0]);
return 0;
}
The above code prints out "hello world."
上面的代码打印出来 "hello world."
How would i print out just "h"? Shouldn't the access x[0]ensure this?
我将如何打印出来"h"？访问不应该x[0]确保这一点吗？
回答by codaddict
You should do:
你应该做：
printf("%c \n", x[0]);
The format specifierto print a char is c. So the format string to be used is %c.
打印字符的格式说明符是c. 所以要使用的格式字符串是%c.
Also to access an array element at a valid index iyou need to say array_name[i]. You should not be using the &. Using &will give you the address of the element.
另外要访问有效索引处的数组元素，i您需要说array_name[i]. 您不应该使用&. 使用&将为您提供元素的地址。
回答by John Carter
Shouldn't the access
x[0]ensure this?
访问不应该
x[0]确保这一点吗？
No, because the &in &x[0]gets the address of the first element of the string (so it's equivalent to just using x.
不，因为&in&x[0]获取字符串的第一个元素的地址（所以它相当于只使用x.
%swill output all the characters in a string sees the null character at the end of the string (which is implicit for literal strings).
%s将输出字符串中的所有字符看到字符串末尾的空字符（这对于文字字符串是隐式的）。
In order to print out a character rather than the whole string, use the character format specifier, %cinstead.
为了打印出一个字符而不是整个字符串，请改用字符格式说明符%c。
Note that printf("%s \n", x[0]);would be invalid since x[0]is of type charand %sexpects a char *.
请注意，这printf("%s \n", x[0]);将是无效的，因为x[0]它是类型char并且%s需要一个char *.
回答by Paul Tomblin
#include <stdio.h>
int main(void){
char x [] = "hello world.";
printf("%c \n", x[0]);
return 0;
}
回答by ssfrr
A string in C is an array of characters with the last character being the NULL character \0. When you use the %sstring specifier in a printf, it will start printing chars at the given address, and continue until it hits a null character. To print a single character use the %cformat string instead.
C 中的字符串是一个字符数组，最后一个字符是 NULL 字符\0。当您%s在 a 中使用字符串说明符时printf，它将开始在给定地址打印字符，并继续直到遇到空字符。要打印单个字符，请改用%c格式字符串。
回答by sadananda salam
Since a string in C is an array of characters. This statement will print the first character.
因为 C 中的字符串是一个字符数组。该语句将打印第一个字符。
printf("%c \n", "hello world."[0]);
