c - 如果输入到字符数组中的字符数少于指定的空格数，会发生什么情况

Question

char ch_arry[20] = { S, A, L, L, Y};
printf( "%s", ch_arry[] );

它会用空字符填充数组的末尾吗？

Answer 1

来自C标准(6.7.9初始化)

19 The initialization shall occur in initializer list order, each initializer provided for a particular subobject overriding any previously listed initializer for the same subobject;151) all subobjects that are not initialized explicitly shall be initialized implicitly the same as objects that have static storage duration.

和

10 If an object that has automatic storage duration is not initialized explicitly, its value is indeterminate. If an object that has static or thread storage duration is not initialized explicitly, then:

— if it has pointer type, it is initialized to a null pointer;

— if it has arithmetic type, it is initialized to (positive or unsigned) zero;

— if it is an aggregate, every member is initialized (recursively) according to these rules, and any padding is initialized to zero bits;

所以如果你有这样的声明

char ch_arry[20] = { 'S', 'A', 'L', 'L', 'Y'};

然后数组中所有未显式初始化的元素都将用零隐式初始化。