CODEWITHSUNDEEP
cruntime-errorruntimeexception
Ankit Mishra
Ankit Mishra

Reputation: 31

My C Program Keep Crashing

i am trying to create an program to generate empty files. but when it try to run the program it crashes after taking inputs from the console .

#include<stdio.h>
#include<string.h>
#include<stdlib.h>

int create(char* filename)
{
    char filext[10];
    printf("\nEnter File Extension :");
    fgets(filext);
        FILE* fp;
        fp = fopen(strcat(filename,strcat(".",filext)),"w");
        if(!fp)
        {
            return 0;
        }
        fclose(fp);
        return 1;

}
int main(int argc , char* argv[])
{
    int f;
    int i;
    char buffer[33];
    if (argc == 3)
    {
        for(i = 0; i < atoi(argv[2]) ; i++)
        {
            f = create(strcat(argv[1],itoa(i,buffer,10)));
            if(f==0)
            {
                printf("error in creating files . check uac!!!");
            }
            else{
                printf("\nfile Created ...\n");
            }
        }
    }
    else{
        printf("syntax Error");
    }
    return 0;
}

when I try to run this program I get the following output

F:\selfcreatedtools\filegen>gcc gen.c

F:\selfcreatedtools\filegen>a level 100

Enter File Extension :php

after entering the extension the program crashes. i am a beginner in c programming.

Upvotes: 0

Views: 181

Answers (1)

J...S
J...S

Reputation: 5207

Your main problem lies in the strcat(".",filext) part of
fp = fopen(strcat(filename,strcat(".",filext)),"w");

Try

strcat(filename, ".");
strcat(filename, filext);
fp = fopen(filename, "w");


And it might be better if the function definition header was made int create(char filename[SIZE]) (where SIZE is a value less than the size filename will be) instead of int create(char* filename) since you are using strcat() to modify the string in the user-defined function create(). You wouldn't want illegal memory accesses that would cause errors if the string encroaches upon the memory allotted to something else.

A similar problem is there with using strcat() to modify the string at argv[1] as pointed out by Jonathan Leffler for which BLUEPIXY has provided a solution in the comments.

Upvotes: 1

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