所以我制作了一个模拟Tic-Tac-Toe游戏的程序并用valgrind运行它，它说我有内存泄漏。造成这种泄漏的原因是什么？如何解决？
以下是valgrind的输出：
==15253==
==15253== HEAP SUMMARY:
==15253== in use at exit: 72,704 bytes in 1 blocks
==15253== total heap usage: 37 allocs, 36 frees, 76,864 bytes allocated
==15253==
==15253== 72,704 bytes in 1 blocks are still reachable in loss record 1 of 1
==15253== at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==15253== by 0x4EC5B1F: ??? (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.22)
==15253== by 0x40104E9: call_init.part.0 (dl-init.c:72)
==15253== by 0x40105FA: call_init (dl-init.c:30)
==15253== by 0x40105FA: _dl_init (dl-init.c:120)
==15253== by 0x4000CF9: ??? (in /lib/x86_64-linux-gnu/ld-2.23.so)
==15253==
==15253== LEAK SUMMARY:
==15253== definitely lost: 0 bytes in 0 blocks
==15253== indirectly lost: 0 bytes in 0 blocks
==15253== possibly lost: 0 bytes in 0 blocks
==15253== still reachable: 72,704 bytes in 1 blocks
==15253== suppressed: 0 bytes in 0 blocks
==15253==
==15253== For counts of detected and suppressed errors, rerun with: -v
==15253== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
以下是代码：
main.cpp中：
#include <iostream>
#include "../include/Board.h"
using namespace std;
/**
* Main function that is run.
* @return: 0 on exit success
*/
int main() {
Board b;
int r, c;
int moveCount = 0;
cout << "* * * * * Welcome to the Tic-Tac-Toe game! * * * * *" << endl;
cout << "Enter numbers 1, 2, or 3 when prompted for coordinates of your move." << endl;
cout << b.toString() << endl;
// Loops until there are no more possible moves.
while(moveCount < 9) {
// Prompts for coordinates to make a move.
do {
if(moveCount % 2 == 0) {
cout << "Player X's turn, enter the row and column of your move.\nRow #:";
}
else {
cout << "Player O's turn, enter the row and column of your move.\nRow #:";
}
cin >> r;
cout << "Column #:";
cin >> c;
// Checks if the move is valid.
if(b.canPut((r - 1), (c - 1)) != 1) {
cout << "\nInvalid move, re-enter the desired coordinates.\n" << endl;
}
}while(b.canPut((r - 1), (c - 1)) != 1);
// Makes the move.
if(moveCount % 2 == 0) {
b.makeMove((r - 1), (c - 1), X);
}
else {
b.makeMove((r - 1), (c - 1), O);
}
cout << b.toString() << endl;
// Checks if there is a winner and breaks the loop if there is.
if(b.checkWinner() != 0)
break;
moveCount++;
}
// Prints the appropriate statement base on the winning status, if any.
if(moveCount == 9) {
cout << "\nGame over, stalemate." << endl;
}
else {
if(b.checkWinner() == X) {
cout << "\nPlayer X has won!!!" << endl;
}
else if(b.checkWinner() == O) {
cout << "\nPlayer O has won!!!" << endl;
}
}
return 0;
}
Board.h：
#ifndef BOARD_H
#define BOARD_H
#include <string>
#define X 1
#define O 5
#define SIZE 3
/**
* Board class for tic-tac-toe project.
*/
class Board {
private:
int **grid;
public:
Board();
~Board();
int checkWinner();
int canPut(int r, int c);
void makeMove(int r, int c, int val);
std::string toString();
};
#endif
Board.cpp：
#include "../include/Board.h"
#include <string>
using namespace std;
/**
* Constructor for a Board object.
*/
Board::Board() {
grid = new int*[SIZE];
// Creates all the 1D arrays to make the 2D array.
for(int ctr = 0; ctr < SIZE; ctr++) {
grid[ctr] = new int[SIZE];
for(int i = 0; i < SIZE; i++) {
grid[ctr][i] = 0;
}
}
}
/**
* Destructor for a Board object.
*/
Board::~Board() {
for(int ctr = 0; ctr < SIZE; ctr++) {
delete[] grid[ctr];
}
delete[] grid;
}
/**
* Checks if there is a winner for the current game.
* @return: 0 if no winner, X if X player wins or O if O player wins
*/
int Board::checkWinner() {
int sum;
// Checks all the rows for a winner.
for(int i = 0; i < SIZE; i++) {
sum = 0;
for(int ctr = 0; ctr < SIZE; ctr++) {
sum += grid[i][ctr];
}
if(sum == 3) {
return X;
}
else if(sum == 15) {
return O;
}
}
// Checks all the columns for a winner.
for(int a = 0; a < SIZE; a++) {
sum = 0;
for(int b = 0; b < SIZE; b++) {
sum += grid[b][a];
}
if(sum == 3) {
return X;
}
else if(sum == 15) {
return O;
}
}
// Checks the top-left to bottom-right diagonal for a winner.
sum = 0;
for(int i = 0; i < SIZE; i++) {
sum += grid[i][i];
}
if(sum == 3) {
return X;
}
else if(sum == 15) {
return O;
}
// Checks the top-right to bottom-left diagonal for a winner.
sum = 0;
for(int r = 0, c = SIZE - 1; r < SIZE && c > 0; r++, c--) {
sum += grid[r][c];
}
if(sum == 3) {
return X;
}
else if(sum == 15) {
return O;
}
// Returns zero because after checking all the possibilities, a winner has not been found.
return 0;
}
/**
* Determines if there is an open spot on the board at the given coordinates.
* @param r: the row to be checked
* @param c: the column to be checked
* @return: 1 if there is an open spot, 0 if not
*/
int Board::canPut(int r, int c) {
if(grid[r][c] == 0)
return 1;
return 0;
}
/**
* Simulates making a move for a player.
* @param r: the row to set the value
* @param c: the column to set the value
* @param val: the value to be set at the given coordinates
*/
void Board::makeMove(int r, int c, int val) {
grid[r][c] = val;
}
/**
* Creates a representation of the board as a string.
* @return: string of the board
*/
string Board::toString() {
char a, b, c;
string output = "Board:\n";
// Loops through every line for the 2D array.
for(int ctr = 0; ctr < SIZE; ctr++) {
// Loops through every value of the 1D array being checked.
for(int i = 0; i < SIZE; i++) {
output += ' ';
if(grid[ctr][i] == X) {
output += 'X';
}
else if(grid[ctr][i] == O) {
output += 'O';
}
else {
output += ' ';
}
if(i != (SIZE - 1)) {
output.append(" |");
}
else {
output += '\n';
}
}
// Pads each line with a line of '-' characters.
if(ctr != (SIZE - 1)) {
for(int i = 0; i < (SIZE * 4) - 1; i++) {
output += '-';
}
output += '\n';
}
}
return output;
}
答案 0 :(得分：2)
所以，内存泄漏不是你的问题。在程序执行初始化之前，甚至在执行任何代码之前，都会发生内存泄漏。
Valgrind通常会忽略这些。它有一个文件，其中包含各种平台上各种库中需要忽略的事项列表。也许您使用了一个Valgrind选项，告诉它不要忽略它们，或者它可能还没有正确设置在该平台上的libstdc ++的确切版本。
作为一个不相关的C ++风格的说明，我会说我不太喜欢你在 Board.h 中使用#define。你应该宣布const。
答案 1 :(得分：2)
你的代码看起来不错，但我建议不要使用指针指向网格，这有点棘手。
而不是int **grid，
有int grid[SIZE][SIZE]。
然后你不需要任何新的和删除调用 - 没有内存泄漏源！
除非SIZE非常大并且您尝试在堆栈上分配Board，否则此方法有效。如果SIZE很大，只需在b = new Board()上分配堆。 （不要忘记删除它！）