[考題] 計算機概論 程式輸出問題

[jolinboyfrie (宇)]

考慮以下 C 程式
int fun (int *x) {
     *x += 4;
     return 4 * (*x) –2;
}

void main() {
     int x = 20, y = 30, w,z;
     w = fun(&x) + (x/2);
     z = fun(&y) + (y/2); printf(“%d,%d”, w,z);
}
程式執行後,w, z 的值為何?
a.48與151  b.106與151 c.104與133 d.48與133
答案為b
想請問各位高手他是怎麼運算的啊？

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推 godpam:w=4*24-2+24/2=106
→ godpam:z=4*34-2+34/2=151
→ fatty3321:這題出題老師其實還蠻溫柔的XD如果是我一定把a或c挑一個
→ fatty3321:改106XD
推 j16598231:x=20，呼叫後x變24。w=94+24/2
→ Kingofjungle:不懂原理的話GOOGLE CALL BY VALUE，CALL BY ADRESS