Question

我正在尝试编写一个程序来打印范围[a，b]中的所有回文。到目前为止我写过这个，但输入a，b的值后没有打印。缺什么？

#include "stdafx.h"
#include <iostream>
using namespace std;

int t = 0, rmd, z, a, b;

int reverse() {
    while (z != 0) {
        rmd = z% 10;
        t = t * 10 + rmd;
        z/= 10;
        }

    return t;
}

int palin() {
    if (a == reverse()) {
        return 1;
    }
    else 
        return 0;

}

int main() {

    cout << "a: "; cin >> a;
    cout << "b: "; cin >> b;

    while (a <= b) {
        z = a;
        if (palin()) 
            cout << a << endl;
        a++;
    }
    system("pause");
    return 0;
}

Answer 1

问题是t函数的变量reverse() 不是本地的。它的值仍然存在于下面的调用中，因此反向结果变为与实际调用无关的垃圾。

您需要t将reverse()设为本地reverse()才能解决此问题。

一般来说，养成一种习惯，即在不破坏代码的情况下，将变量放在最内层范围内。在这种情况下，这将是t main函数的范围，以及剩余变量的palin范围; a应以@objc protocol UIASyntheticEvents { static func sharedEventGenerator() -> UIASyntheticEvents //@property(readonly) struct __IOHIDEventSystemClient *ioSystemClient; // @synthesize ioSystemClient=_ioSystemClient; var voiceOverStyleTouchEventsEnabled: Bool { get set } var activePointCount: UInt64 { get set } //@property(nonatomic) CDStruct_3eca2549 *activePoints; // @synthesize activePoints=_activePoints; var gsScreenScale: Double { get set } var gsScreenSize: CGSize { get set } var screenSize: CGSize { get set } var screen: UIScreen { get set } var onScreenRect: CGRect { get set } func sendPinchCloseWithStartPoint(_: CGPoint, endPoint: CGPoint, duration: Double, inRect: CGRect) func sendPinchOpenWithStartPoint(_: CGPoint, endPoint: CGPoint, duration: Double, inRect: CGRect) func sendDragWithStartPoint(_: CGPoint, endPoint: CGPoint, duration: Double, withFlick: Bool, inRect: CGRect) func sendRotate(_: CGPoint, withRadius: Double, rotation: Double, duration: Double, touchCount: UInt64) func sendMultifingerDragWithPointArray(_: UnsafePointer<CGPoint>, numPoints: Int32, duration: Double, numFingers: Int32) func sendPinchCloseWithStartPoint(_: CGPoint, endPoint: CGPoint, duration: Double) func sendPinchOpenWithStartPoint(_: CGPoint, endPoint: CGPoint, duration: Double) func sendFlickWithStartPoint(_: CGPoint, endPoint: CGPoint, duration: Double) func sendDragWithStartPoint(_: CGPoint, endPoint: CGPoint, duration: Double) func sendTaps(_: Int, location: CGPoint, withNumberOfTouches: Int, inRect: CGRect) func sendDoubleFingerTap(_: CGPoint) func sendDoubleTap(_: CGPoint) func _sendTap(_: CGPoint, withPressure: Double) func sendTap(_: CGPoint) func _setMajorRadiusForAllPoints(_: Double) func _setPressureForAllPoints(_: Double) func moveToPoints(_: UnsafePointer<CGPoint>, touchCount: UInt64, duration: Double) func _moveLastTouchPoint(_: CGPoint) func liftUp(_: CGPoint) func liftUp(_: CGPoint, touchCount: UInt64) func liftUpAtPoints(_: UnsafePointer<CGPoint>, touchCount: UInt64) func touchDown(_: CGPoint) func touchDown(_: CGPoint, touchCount: UInt64) func touchDownAtPoints(_: UnsafePointer<CGPoint>, touchCount: UInt64) func shake() func setRinger(_: Bool) func holdVolumeDown(_: Double) func clickVolumeDown() func holdVolumeUp(_: Double) func clickVolumeUp() func holdLock(_: Double) func clickLock() func lockDevice() func holdMenu(_: Double) func clickMenu() func _sendSimpleEvent(_: Int) func setOrientation(_: Int32) func sendAccelerometerX(_: Double, Y: Double, Z: Double, duration: Double) func sendAccelerometerX(_: Double, Y: Double, Z: Double) func _updateTouchPoints(_: UnsafePointer<CGPoint>, count: UInt64) func _sendHIDVendorDefinedEvent(_: UInt32, usage: UInt32, data: UnsafePointer<UInt8>, dataLength: UInt32) -> Bool func _sendHIDScrollEventX(_: Double, Y: Double, Z: Double) -> Bool func _sendHIDKeyboardEventPage(_: UInt32, usage: UInt32, duration: Double) -> Bool //- (_Bool)_sendHIDEvent:(struct __IOHIDEvent *)arg1; //- (struct __IOHIDEvent *)_UIACreateIOHIDEventType:(unsigned int)arg1; func _isEdgePoint(_: CGPoint) -> Bool func _normalizePoint(_: CGPoint) -> CGPoint //- (void)dealloc; func _initScreenProperties() //- (id)init; }作为参数。

Answer 2

您对变量的使用让您感到困惑。每次调用reverse时，实际问题都不是将t设置为零，但是您应该考虑如何使用变量作用域以及实际执行的函数。现在你有2个程序，它们对全局数据执行操作。而是尝试使用接受参数的函数来表达问题，并返回结果。

#include <iostream>

using namespace std;

int reverse(int z) {
    int t = 0;

    int rmd;
    while (z != 0) {
        rmd = z % 10;
        t = t * 10 + rmd;
        z/= 10;
    }

    return t;
}

int palin(int z) {
    return z == reverse(z);
}

int main() {
    int a, b;

    cout << "a: "; cin >> a;
    cout << "b: "; cin >> b;

    while (a <= b) {
        if (palin(a)) {
            cout << a << endl;
        }
        a++;
    }
    system("pause");
    return 0;
}

打印给定范围内的所有回文数

2 个答案: