鍙橀噺綾誨瀷

鍙橀噺鍚嶇粰鎴戜滑鎻愪緵浜嗗湪紼嬪簭涓垜浠彲浠ヤ嬌鐢ㄧ殑絀洪棿淇℃伅銆傛瘡涓彉閲忓湪 C++ 涓兘鏈変竴涓壒瀹氱殑綾誨瀷錛屽畠鍐沖畾鍙橀噺鍦ㄥ唴瀛樹腑鐨勫ぇ灝忓拰甯冨眬錛涘湪璇ュ唴瀛樼┖闂村彲浠ュ瓨鏀懼彇鍊艱寖鍥達紱鍜屼竴緇勫彲浠ュ簲鐢ㄤ簬璇ュ彉閲忕殑鎿嶄綔銆?/p>

涓€涓彉閲忕殑鍚嶇О鍙互鐢卞瓧姣嶃€佹暟瀛楀拰涓嬪垝綰垮瓧絎︾粍鎴愩€傚畠蹇呴』浠ュ瓧姣嶆垨涓嬪垝綰垮紑濮嬨€傚ぇ鍐欏拰灝忓啓鐨勫瓧姣嶆槸涓嶅悓錛屽洜涓?C++ 鏄尯鍒嗗ぇ灝忓啓鐨?

C++ 涓湁浠ヤ笅鍩烘湰鍙橀噺綾誨瀷錛屾垜浠湪涓婁竴鑺傚凡緇忎粙緇嶈繃:

C++ 榪樺厑璁稿畾涔夊悇縐嶅叾浠栫被鍨嬬殑鍙橀噺錛屾垜浠皢鍦ㄥ悗緇珷鑺傚皢浼氫粙緇嶇殑錛屾瘮濡?Enumeration錛屾寚閽堬紝鏁扮粍錛屽紩鐢紝鏁版嵁緇撴瀯鍜岀被銆?/p>

涓嬩竴鑺傚皢浠嬬粛濡備綍瀹氫箟錛屽０鏄庡拰浣跨敤鍚勭綾誨瀷鐨勫彉閲忋€?/p>

C++ 涓彉閲忕殑瀹氫箟

涓€涓彉閲忓畾涔夋剰鍛崇潃鍛婅瘔緙栬瘧鍣紝瀛樺偍鍦ㄥ摢閲屼互鍙婇渶瑕佸灝戠殑瀛樺偍絀洪棿銆傚彉閲忓畾涔夎鎸囧畾鏁版嵁綾誨瀷錛屽悓鏃跺寘鍚綾誨瀷鐨勪竴涓垨澶氫釜鍙橀噺鐨勫垪琛細

    type variable_list;

鍦ㄨ繖閲岋紝type 蹇呴』鏄竴涓湁鏁堢殑 C++ 鏁版嵁綾誨瀷錛屽寘鎷?char錛寃_char錛宨nt錛宖loat錛宒ouble錛宐ool 鎴栬€呬換浣曠敤鎴瘋嚜瀹氫箟鐨勫璞＄瓑銆?strong>variable_list 瑕佸寘鍚竴涓垨澶氫釜鐢遍€楀彿鍒嗛殧鐨勬爣璇嗙銆傚涓嬫槸涓€浜涙湁鏁堢殑澹版槑紺轟緥錛?/p>

    int i, j, k;
    char c, ch;
    float f, salary;
    double d;

int i,j,k; 榪欎竴琛屽悓鏃跺０鏄庡拰瀹氫箟浜嗗彉閲?i錛宩 鍜?k錛岃繖鏉¤鍙ユ寚紺虹紪璇戝櫒鍒涘緩綾誨瀷涓?int錛屽悕縐頒負 i錛宩 鍜?k 鐨勫彉閲忋€?/p>

鍙橀噺鍦ㄥ０鏄庣殑鍚屾椂鍙互榪涜鍒濆鍖?鍒嗛厤涓€涓垵濮嬪€?銆傚垵濮嬪寲鐢變竴涓瓑鍙峰悗闈㈣窡鐫€涓€涓父鏁拌〃杈懼紡濡備笅:

    type variable_name = value;

濡備笅鏄竴浜涚ず渚嬶細

    extern int d = 3, f = 5;    // declaration of d and f. 
    int d = 3, f = 5;           // definition and initializing d and f. 
    byte z = 22;                // definition and initializes z. 
    char x = 'x';               // the variable x has the value 'x'.

娌℃湁鍒濆鍖栫殑瀹氫箟錛氶潤鎬佺被鍨嬬殑鍙橀噺浼氶殣寮忓湴琚垵濮嬪寲涓?NULL(鎵€鏈変綅鍊間負0)錛岃€屽叾浠栫殑鎵€鏈夊彉閲忕殑鍒濆鍊兼槸鏈煡鐨勩€?/p>

C++ 涓彉閲忓０鏄?/h3>

鍙橀噺澹版槑涓虹紪璇戝櫒鎻愪緵淇濊瘉錛屽浜庣粰瀹氱殑綾誨瀷鍜屽悕縐扮殑鍙橀噺鏄敮涓€鐨勶紝浠庤€岀紪璇戝櫒鍦ㄨ繘涓€姝ヨ繘琛岀紪璇戝彉閲忔椂涓嶉渶瑕佸彉閲忕殑瀹屾暣緇嗚妭銆傚彉閲忓０鏄庡彧鏄湪緙栬瘧鏃舵湁鎰忎箟鐨勶紝鍥犱負緙栬瘧鍣ㄥ湪榪涜紼嬪簭鐨勯摼鎺ユ椂闇€瑕佸彉閲忓０鏄庣殑淇℃伅銆?/p>

褰撲綘浣跨敤澶氫釜鏂囦歡錛屽茍涓斾綘鑷繁瀹氫箟鐨勫彉閲忔斁鍦ㄥ叾涓竴涓枃浠墮噷錛屽彉閲忕殑澹版槑灝嗗紼嬪簭鐨勯摼鎺ュ緢鏈夌敤銆傛?zhèn)ㄥ彲浠ヤ娇鐢?extern 鍏抽敭瀛楁潵澹版槑涓€涓斁鍦ㄤ換浣曚綅緗殑鍙橀噺銆傝櫧鐒朵綘鍦ㄤ綘鐨?C++ 紼嬪簭涓綘鍙互澹版槑涓€涓彉閲忓嬈★紝浣嗗畠鍦ㄤ竴涓枃浠朵腑錛屼竴涓嚱鏁版垨涓€鍧椾唬鐮佷腑鍙兘瀹氫箟涓€嬈°€?/p>

紺轟緥

璇曡瘯涓嬮潰鐨勪緥瀛愶紝涓€涓彉閲忓凡緇忓湪欏墮儴榪涜浜嗗０鏄庯紝浣嗗悓鏃跺畠涔熷湪 main 鍑芥暟涓瀹氫箟浜?

    #include <iostream>
    using namespace std;

    // Variable declaration:
    extern int a, b;
    extern int c;
    extern float f;

    int main ()
    {
        // Variable definition:
        int a, b;
        int c;
        float f;

        // actual initialization
        a = 10;
        b = 20;
        c = a + b;

        cout << c << endl ;

        f = 70.0/3.0;
        cout << f << endl ;

        return 0;
    }

涓婇潰鐨勪唬鐮佺紪璇戝拰鎵ц鍚庯紝瀹冧駭鐢熶互涓嬬粨鏋?

    30
    23.3333

鐩稿悓鐨勬蹇典篃鍙互搴旂敤浜庡嚱鏁板０鏄庯紝褰撲綘瀵逛竴涓嚱鏁拌繘琛屽０鏄庢椂錛屽畠鐨勫畾涔夊彲浠ュ湪鍏朵粬浠諱綍鍦版柟銆備緥濡?

    // function declaration
    int func();

    int main()
    {
        // function call
        int i = func();
    }

    // function definition
    int func()
    {
        return 0;
    }

宸﹀€煎拰鍙沖€?/h3>

C++ 涓湁涓ょ琛ㄨ揪寮忥細

• 宸﹀€鹼細鎸囧悜鍐呭瓨浣嶇疆鐨勮〃杈懼紡縐頒負宸﹀€艱〃杈懼紡銆備竴涓乏鍊煎彲鑳藉嚭鐜板湪璧嬪€艱鍙ョ殑宸﹁竟鎴栧彸杈廣€?/li>
• 鍙沖€鹼細鍙沖€兼槸鎸囦竴涓暟鎹€煎瓨鍌ㄥ湪鏌愪釜鍐呭瓨鍦板潃涓€備竴涓彸鍊兼槸涓€涓〃杈懼紡錛屽畠涓嶈兘琚祴鍊鹼紝榪欐剰鍛崇潃涓€涓彸鍊煎彲鑳藉嚭鐜板湪璧嬪€艱鍙ョ殑鍙寵竟錛岃€屼笉鏄乏杈廣€?/li>

鍙橀噺鏄乏鍊?鍥犳鍙兘浼氬嚭鐜板湪璧嬪€艱鍙ョ殑宸﹁竟銆傛暟瀛楀瓧闈㈠€兼槸鍙沖€鹼紝鍥犳涓嶈兘琚祴鍊鹼紝涓嶈兘鍑虹幇璧嬪€艱鍙ョ殑鍦ㄥ乏杈廣€備笅闈㈡槸涓€涓湁鏁堢殑璇彞:

    int g = 20;

浣嗗涓嬪嵈涓嶆槸涓€涓湁鏁堢殑璧嬪€艱鍙ワ紝浼氫駭鐢熺紪璇戞湡閿欒:

    10 = 20錛?/code>