使用引用

#include <iostream>
using namespace std;
struct Time{
	int h;
	int m;
	int s;
};
void timeCompute(Time &t, int sec){	//引用作為形參 
	t.m = t.m + (t.s + sec)/60;	//分鐘的進位 
	t.s = (t.s + sec)%60;   //秒數位計算後剩餘的時間
	t.h = t.h + t.m/60;	//小時的進位
	t.m = t.m%60;   //分鐘位計算後剩餘的時間
	t.h = t.h%24;   //小時位取餘實現24小時制
} 
int main(){
	int repeat,sec;	//重覆次數 
	cin >> repeat;
	struct Time t;  //創建一個time類型的結構體 t
	for(int i = 0; i < repeat; i++){
		scanf("%d:%d:%d", &t.h, &t.m, &t.s); //存入結構體 h m s 
		cin >> sec;	//要度過的秒數 
		timeCompute(t,sec);
		cout << t.h << ":" << t.m << ":" << t.s << endl; 
	}
	return 0;
}

複雜且笨的寫法

/*
 * @Author: DEFT:[email protected]  V:NOTFOUND6O6 
 * @Date: 2023-02-23 19:44:59
 * @LastEditors: Please set LastEditors
 * @LastEditTime: 2023-03-03 15:19:55
 * @FilePath: \WenkaiC\time_conversion.cpp
 * @Description: 
 * 
 * Copyright (c) 2023 by 1zPeasy, All Rights Reserved. 
 */
#include <iostream>
#include <string>
using namespace std;

int main(int argc, char const *argv[])
{
    int repeat,hour,minute,second,spend_second,add_minute;
    cin >> repeat;        //輸入重覆次數
    
    for (int i = 0; i < repeat; i++)
    {
        int num_scanned = scanf("%d:%d:%d", &hour, &minute, &second);   //輸入時間
        cin >> spend_second;    //輸入要度過的秒數
        second = second + spend_second;
        add_minute = second/60; //計算秒數加完到底是要進位多少分鐘
        second = second%60; //計算進位分鐘後還剩多少秒
        minute = minute + add_minute;   //進位後的分鐘
        //判斷minute是否需要進位
        if (minute >=60)    //如果更新後的分鐘大於等於60
        {
            hour = hour + minute/60;    //計算更新後的hour
            minute = minute % 60;   //分鐘數進位後minute還剩多少分鐘
        }
        //判斷hour是否需要進位
        if (hour  >= 24)    //如果進位後小時數大於=24
        {
            hour = hour %  24;  //更新後的小時數
        }
        cout << "time: " << hour << ":" << minute << ":" << second << endl;
        //判斷scanf返回值用來處理錯誤
        if (num_scanned != 3) {
        
        }
    }
    

    return 0;
}