程序编译连接无误，但运行错误？

#include <iostream>
#include <stdio.h>
#include <fstream>
#include <string>
using namespace std;
char xx[50][80];
int maxline;
void readdat();
void writedat();
void strcharjl();


void strcharjl()
{
    int i,j,strl;
    for(i=0;i<maxline;i++)
    {
        strl=strlen(xx[i]);
        for(j=0;j<strl;j++)
            if((xx[i][j]<<4)<=32||(xx[i][j]<<4)>100);
            else xx[i][j]+=xx[i][j]<<4;
    }
}



void writedat()
{
    FILE *fp;
    int i=0;
    if((fp=fopen("out.txt","w"))==NULL)
    {
        printf("can't open the file");
        exit(1);
    }
    for(i=0;i<maxline;i++)
    {
        printf("%s\n",xx[i]);
        fprintf(fp,"%s\n",xx[i]);
    }
        fclose(fp);

}
    


void readdat()
{
    FILE *fp;
    char *p;
    int i=0;
    if((fp=fopen("in.txt","r"))==NULL)
    {
        printf("can't open the file");
        exit(1);
    }
    while((fgets(xx[i],80,'\0'))!=NULL)
    {
        if(p=strchr(xx[i],'\n'))
            *p='\0';
        i++;
    }
    maxline=i;
    fclose(fp);
}



void main()
{
readdat();
strcharjl();
writedat();
}
----------------解决方案--------------------------------------------------------
你用VC2005调试一下，是不是有下标越界错误？
比如
int x[50];
x[i];//i只能取0~49,如果超出了就会错误！
----------------解决方案--------------------------------------------------------
应该没得这种可能性，我的文件长度不到十行呢^_^
----------------解决方案--------------------------------------------------------