C++姹傜粷瀵瑰€煎嚱鏁扮殑鍙戝睍鍘嗙▼濡備笅锛?/p>

1. 鏈€鍒濈殑鐗堟湰锛氭渶鍒濈殑缁濆鍊煎嚱鏁版槸閫氳繃绠€鍗曠殑if璇彞鏉ュ疄鐜扮殑锛屽垽鏂緭鍏ョ殑鍊兼槸姝ｆ暟杩樻槸璐熸暟锛岀劧鍚庤繑鍥炲搴旂殑缁濆鍊笺€?/li>

int abs(int num) {
    if (num < 0) {
        return -num;
    } else {
        return num;
    }
}

2. 鏁板搴撳嚱鏁帮細闅忕潃C++鏍囧噯搴撶殑鍙戝睍锛屾暟瀛﹀簱涓彁渚涗簡姹傜粷瀵瑰€肩殑鍑芥暟fabs()锛屽彲浠ョ洿鎺ヨ皟鐢ㄨ鍑芥暟鏉ユ眰缁濆鍊笺€?/li>

#include <cmath>

int abs(int num) {
    return fabs(num);
}

3. 妯℃澘鍑芥暟锛氫负浜嗘彁楂樺嚱鏁扮殑閫氱敤鎬э紝鍙互浣跨敤妯℃澘鍑芥暟鏉ュ疄鐜扮粷瀵瑰€煎嚱鏁帮紝鍙互鏀寔鏇村绫诲瀷鐨勫弬鏁般€?/li>

template <typename T>
T abs(T num) {
    return (num < 0) ? -num : num;
}

4. C++鏍囧噯搴撶殑std::abs()鍑芥暟锛欳++11鏍囧噯寮曞叆浜唖td::abs()鍑芥暟锛屽彲浠ョ敤鏉ユ眰缁濆鍊硷紝鍚屾椂鏀寔澶氱鏁板€肩被鍨嬨€?/li>

#include <cstdlib>

int main() {
    int num = -5;
    int result = std::abs(num);
    return 0;
}

5. C++17鏍囧噯鐨剆td::abs()鍑芥暟澧炲姞浜嗗std::complex绫诲瀷鐨勬敮鎸併€?/li>

#include <complex>

int main() {
    std::complex<double> num(-3.0, 4.0);
    double result = std::abs(num);
    return 0;
}

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