why i get this run time error

This is a discussion on why i get this run time error within the C Programming forums, part of the General Programming Boards category; i get on line 47 error when it tries to close the file why the fopen return NULL? and even ...

  1. #1
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    Oct 2008
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    1,535

    why i get this run time error

    i get on line 47 error
    when it tries to close the file

    why the fopen return NULL?

    and even if i eliminate every fclose
    its doing the same this inside the function
    ??

    Code:
    #include <stdio.h>
    #include <string.h>
    #include <stdlib.h>
     
    
     
    typedef struct vote {
    	char name [30];
    	int id,type,candidate;
    } vote;
    void report(FILE* college[3], FILE* arr[10], char* canceled);
    // Fuction returns the minimal id
    int getMin(int eof[],vote [],int *);
    // Function checks a vote record correct
    int votecheck(vote ,vote [],int i);
    // Function reads the next record from "college" file
    int readFrom(FILE *,vote [],int);
    
    
    
    int main ()
    {
    FILE* f[10];
    FILE* c[3];
    char  name[3]="canceled";
    
    c[0]=fopen("c:\\file1","r");//vote files ,each file represents the votes from a college
    c[1]=fopen("c:\\file2","r");
    c[3]=fopen("c:\\file3","r");
    f[0]=fopen("c:\\cfile1","w");//condidate files
    f[1]=fopen("c:\\cfile2","w");
    f[2]=fopen("c:\\cfile3","w");
    f[3]=fopen("c:\\cfile4","w");
    f[4]=fopen("c:\\cfile5","w");
    f[5]=fopen("c:\\cfile6","w");
    f[6]=fopen("c:\\cfile7","w");
    f[7]=fopen("c:\\cfile8","w");
    f[8]=fopen("c:\\cfile9","w");
    f[9]=fopen("c:\\cfile10","w");
     
    fclose(c[0]);
    fclose(c[1]);
    fclose(c[2]);
    fclose(f[0]);
    fclose(f[1]);
    fclose(f[2]);
    fclose(f[3]);
    fclose(f[4]);
    fclose(f[5]);
    fclose(f[6]);
    fclose(f[7]);
    fclose(f[8]);
    fclose(f[9]);
     
    report(c, f, name);
    	return 0;
    }
    void  report(FILE *college[3], FILE *arr[10], char* canceled){
    	FILE *cancel;
    	vote currtable[3], // array for three current "college" records
    		votable[3],    // array for checking the records with the same "id"
    		current;	   // struct for the current "college" record	
    	int i,j,idmin,index,flag,eof[3];
    	if(!(cancel=fopen("c:\\canceled","w"))) exit(1);
    	
    	for(i=0;i<3;i++)
    		eof[i]= readFrom(college[i],currtable,i);
    // main loop	
    	while(eof[0]!=EOF||eof[1]!=EOF||eof[2]!=EOF){
    		idmin=getMin(eof,currtable,&index);
    		for(i=flag=0;i<3;i++)
    			if(i!=index && eof[i]!=EOF && currtable[i].id==idmin)
    				flag=3;
    		if(flag){
    		fprintf(cancel,"%s%d%d\n",currtable[index].name,idmin,flag);
    			for(i=0;i<3;i++)
    				while(eof[i]!=EOF && currtable[i].id==idmin)
    				eof[i]=readFrom(college[i],currtable,i);
    			continue;
    		}
    //Filling struct table for the minimal id
    		votable[0]=currtable[index];
    		i=1;
    		while(eof[index]!=EOF && i<3){
    			eof[index]=fscanf(college[index],"%30s%9d%1d%1d%*c",
    current.name,&current.id,&current.type,&current.candidate);
    		if(current.id!=idmin){
    			for(j=0;j<i;j++)
    				fprintf(arr[votable[j].candidate],"%9d%d%d\n",
    idmin,index,votable[j].type);
    		currtable[index]=current;
    		break;
    		}
    		else{
    			flag=votecheck(current,votable,i);
    			if(flag){				fprintf(cancel,"%s%d%d\n",currtable[index].name,idmin,flag);
    			while(eof[index]!=EOF && currtable[index].id==idmin)
    			eof[index]=readFrom(college[index],currtable,index);
    			break;
    			}
    			else
    				votable[i++]=current;
    		}//else
    	}//while
    	if(i<3)  continue;
    		if(eof[index]!=EOF)
    		eof[index]=fscanf(college[index],"%30[^\n]%9d%1d%1d%*c",
    current.name,&current.id,&current.type,&current.candidate);
    		if(eof[index]==EOF ||current.id!=idmin ){
    			for(j=0;j<i;j++)
    				fprintf(arr[votable[j].candidate],"%9d%d%d\n",
    idmin,index,votable[j].type);		
    			currtable[index]=current;
    		}
    		else{			fprintf(cancel,"%s%d%d\n",votable[0].name,idmin,2);
    	while(eof[index]!=EOF && currtable[index].id==idmin)
    		eof[index]=readFrom(college[index],currtable,index);
    		}
    	}// main loop - while
    	fclose(cancel);
    }// report
    
    int votecheck(vote curr,vote arr[],int i){
    	int j,count;
    	for(j=count=0;j<i;j++){
    		if(curr.candidate==arr[j].candidate)
    			return 1;
    		if(curr.type==1 && arr[j].type==1)
    			return 2;
    		if(curr.type==2 && arr[j].type==2)
    			count++;
    		if(count>1)	return 2;
    	}
    	return 0;
    }
    
    int readFrom(FILE *coll,vote table[],int i){
    	return fscanf(coll,"%30[^\n]%9d%1d%1d%*c",table[i].name,
    				&table[i].id,&table[i].type,&table[i].candidate);
    }	
    
    int getMin(int eof[],vote table[],int *index){
    	int i,idmin;
    	for(i=0,idmin=999999999;i<3;i++)
    		if(eof[i]!=EOF && table[i].id<idmin){
    				idmin=table[i].id;
    				*index=i;
    		}
    	return idmin;			
    }

  2. #2
    30 Helens Agree neandrake's Avatar
    Join Date
    Jan 2002
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    640
    You open 10 files, then close all 10 of them, then proceed to try and process reports on the data in files you've closed...
    Environment: OS X, GCC / G++
    Codes: Java, C#, C/C++
    AOL IM: neandrake, Email: neandrake (at) gmail (dot) com

  3. #3
    Banned
    Join Date
    Oct 2008
    Posts
    1,535
    thanks i progressed from there
    why i get null passed in to the function
    why the "c" file array gets NULL
    because of it i still get the same bug
    i got these files:
    file1:
    donald 666666666 1 3
    john 777777777 1 0
    alex 888888888 1 1
    jdoe 999999999 1 2
    file2:
    daniel 000001111 1 3
    green 000003333 1 4
    alex 888888888 1 1
    jdoe 999999999 1 2
    file3:
    daniel 000001111 1 3
    tom 000002222 1 0
    alex 888888888 1 1
    jdoe 999999999 1 2

    Code:
    #include <stdio.h>
    #include <string.h>
    #include <stdlib.h>
     
    
     
    typedef struct vote {
    	char name [30];
    	int id,type,candidate;
    } vote;
    void report(FILE* college[3], FILE* arr[10], char* canceled);
    // Fuction returns the minimal id
    int getMin(int eof[],vote [],int *);
    // Function checks a vote record correct
    int votecheck(vote ,vote [],int i);
    // Function reads the next record from "college" file
    int readFrom(FILE *,vote [],int);
    
    
    
    int main ()
    {
    FILE* f[10];
    FILE* c[3];
    char  name[3]="canceled";
    
    c[0]=fopen("c:\\file1","r");//vote files ,each file represents the votes from a college
    c[1]=fopen("c:\\file2","r");
    c[3]=fopen("c:\\file3","r");
    f[0]=fopen("c:\\cfile1","w");//condidate files
    f[1]=fopen("c:\\cfile2","w");
    f[2]=fopen("c:\\cfile3","w");
    f[3]=fopen("c:\\cfile4","w");
    f[4]=fopen("c:\\cfile5","w");
    f[5]=fopen("c:\\cfile6","w");
    f[6]=fopen("c:\\cfile7","w");
    f[7]=fopen("c:\\cfile8","w");
    f[8]=fopen("c:\\cfile9","w");
    f[9]=fopen("c:\\cfile10","w");
    
    report(c, f, name);
    
    fclose(c[0]);
    fclose(c[1]);
    fclose(c[2]);
    fclose(f[0]);
    fclose(f[1]);
    fclose(f[2]);
    fclose(f[3]);
    fclose(f[4]);
    fclose(f[5]);
    fclose(f[6]);
    fclose(f[7]);
    fclose(f[8]);
    fclose(f[9]);
     
    
    	return 0;
    }
    void  report(FILE *college[3], FILE *arr[10], char* canceled){
    	FILE *cancel;
    	vote currtable[3], // array for three current "college" records
    		votable[3],    // array for checking the records with the same "id"
    		current;	   // struct for the current "college" record	
    	int i,j,idmin,index,flag,eof[3];
    	if(!(cancel=fopen("c:\\canceled","w"))) exit(1);
    	
    	for(i=0;i<3;i++)
    		eof[i]= readFrom(college[i],currtable,i);
    // main loop	
    	while(eof[0]!=EOF||eof[1]!=EOF||eof[2]!=EOF){
    		idmin=getMin(eof,currtable,&index);
    		for(i=flag=0;i<3;i++)
    			if(i!=index && eof[i]!=EOF && currtable[i].id==idmin)
    				flag=3;
    		if(flag){
    		fprintf(cancel,"%s%d%d\n",currtable[index].name,idmin,flag);
    			for(i=0;i<3;i++)
    				while(eof[i]!=EOF && currtable[i].id==idmin)
    				eof[i]=readFrom(college[i],currtable,i);
    			continue;
    		}
    //Filling struct table for the minimal id
    		votable[0]=currtable[index];
    		i=1;
    		while(eof[index]!=EOF && i<3){
    			eof[index]=fscanf(college[index],"%30s%9d%1d%1d%*c",
    current.name,&current.id,&current.type,&current.candidate);
    		if(current.id!=idmin){
    			for(j=0;j<i;j++)
    				fprintf(arr[votable[j].candidate],"%9d%d%d\n",
    idmin,index,votable[j].type);
    		currtable[index]=current;
    		break;
    		}
    		else{
    			flag=votecheck(current,votable,i);
    			if(flag){				fprintf(cancel,"%s%d%d\n",currtable[index].name,idmin,flag);
    			while(eof[index]!=EOF && currtable[index].id==idmin)
    			eof[index]=readFrom(college[index],currtable,index);
    			break;
    			}
    			else
    				votable[i++]=current;
    		}//else
    	}//while
    	if(i<3)  continue;
    		if(eof[index]!=EOF)
    		eof[index]=fscanf(college[index],"%30[^\n]%9d%1d%1d%*c",
    current.name,&current.id,&current.type,&current.candidate);
    		if(eof[index]==EOF ||current.id!=idmin ){
    			for(j=0;j<i;j++)
    				fprintf(arr[votable[j].candidate],"%9d%d%d\n",
    idmin,index,votable[j].type);		
    			currtable[index]=current;
    		}
    		else{			fprintf(cancel,"%s%d%d\n",votable[0].name,idmin,2);
    	while(eof[index]!=EOF && currtable[index].id==idmin)
    		eof[index]=readFrom(college[index],currtable,index);
    		}
    	}// main loop - while
    	fclose(cancel);
    }// report
    
    int votecheck(vote curr,vote arr[],int i){
    	int j,count;
    	for(j=count=0;j<i;j++){
    		if(curr.candidate==arr[j].candidate)
    			return 1;
    		if(curr.type==1 && arr[j].type==1)
    			return 2;
    		if(curr.type==2 && arr[j].type==2)
    			count++;
    		if(count>1)	return 2;
    	}
    	return 0;
    }
    
    int readFrom(FILE *coll,vote table[],int i){
    	return fscanf(coll,"%30s%9d%1d%1d%*c",table[i].name,
    				&table[i].id,&table[i].type,&table[i].candidate);
    }	
    
    int getMin(int eof[],vote table[],int *index){
    	int i,idmin;
    	for(i=0,idmin=999999999;i<3;i++)
    		if(eof[i]!=EOF && table[i].id<idmin){
    				idmin=table[i].id;
    				*index=i;
    		}
    	return idmin;			
    }

  4. #4
    30 Helens Agree neandrake's Avatar
    Join Date
    Jan 2002
    Posts
    640
    Please search first:
    fopen - C++ Reference

    Read the part about opening files with "r" mode.
    Environment: OS X, GCC / G++
    Codes: Java, C#, C/C++
    AOL IM: neandrake, Email: neandrake (at) gmail (dot) com

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