初始化動態配置陣列元素值為0

#include <iostream> using namespace std; int main(){ int *a = new int[5]; int *b = new int[5](); int *p = a; int *q = a + 5; int *r = b; int *s = b + 5; while( p != q ) cout << *(p++) << " "; cout << endl; while( r != s ) cout << *(r++) << " "; cout << endl; int c[5]; static int d[5]; p = c; q = c + 5; r = d; s = d + 5; while( p != q ) cout << *(p++) << " "; cout << endl; while( r != s ) cout << *(r++) << " "; cout << endl; return 0; }

Output:

-1819044973 -1819044973 -1819044973 -1819044973 -1819044973 0 0 0 0 0 -1081662640 -16121856 -1081662696 134538581 134538432 0 0 0 0 0

int *b = new int[5]();

只需在後面加上"( )"即可將動態配置的陣列之元素值初始為0, 另外, 因為在此scope的陣列a並非static or extern, 所以並不會自動初始化值為0 (初值為garbage)

int c[5];
static int d[5];

c之初值為garbage, d是static, 會自動初始化其元素值為0

Note:

*(p++)

等同於

*p++

因為++的優先權比*高