二维数组求最大值

#include<iostream>
#include <stdio.h> 
using namespace std;

FILE *fpRead=fopen("input.txt","r");

char cgetchar(){
	char c;
	fscanf(fpRead,"%c",&c);
	return c;
}

int getnum(){
	char c;
	int num = 0, fuhao = 1;
	while((c = cgetchar()) != EOF && (‘0‘ > c || ‘9‘ < c) && c != ‘-‘);
	if(c == ‘-‘) fuhao = -1;
	else num = c - ‘0‘;
	while((c = cgetchar()) != EOF && ‘0‘ <= c && ‘9‘ >= c){
		num = num * 10 + c - ‘0‘;
	}
	return num * fuhao;
}

int main ()
{
    int x,y,i,j,m=0,A[100][100];
 
    x = getnum();
	y = getnum();
    if(x>100||y>100)
    {
        cout<<"请重新输入：";
        cin>>x>>y;
    }
    for(i=0;i<x;i++)
    {
        for(j=0;j<y;j++)
        {
            A[i][j] = getnum();
            printf("%d ", A[i][j]); 
        }
        printf("\n");
 
    }
    int sum[100]={0},max=0,result=A[0][0];
 
    for(i=0;i<x;i++)//确定子数组的最大上界（为第i行）
    {
        while(m+i<x)//确定子数组有m+i行
        {
            //把子数组当成一位数组一样，求最大子数组的和
            for(j=0;j<y;j++)
            {
                sum[j]=sum[j]+A[m+i][j];
 
            }
            max=0;
            for(j=0;j<y;j++)
            {
                if(max+sum[j]>sum[j])
                {
                    max=max+sum[j];
                }
                else
                {
                    max=sum[j];
                }
                if(max>result)
                {
                    result=max;
                }
            }
            m++;//是子数组的行数+1
        }
		m=0;
		for(j=0;j<y;j++)
		{
			sum[j]=0;
		}
	}
	cout<<result;
	return 0;
}