How can I write c program to create dos command?

Question

Input:
arr = {'a', 'b'}, length = 3

Output:
aaa
aab
aba
abb
baa
bab
bba
bbb

Answer 1

Step 1: Write following code.

    #include <stdio.h>
    void main (int count,char * argv[])
    {
    int i;
    FILE *ptr;
    char *str;
    char ch;
    if (count==1)
    {
    printf("The syntax of the command is incorrect.\n");
    }

    for (i=1;i<count;i++)
    {
    ptr=fopen(argv[i],"r");
    if (ptr==NULL)
    {
    printf("The system cannot find the file specified.");
    if (count>2)
    printf("\nError occurred while procesing : %s.\n",argv[i]);
    }

    else
    {
    if (count>2)
    {
    printf("%s\n\n",argv[i]);
    }

    while ((ch=getc(ptr))!=-1)
    printf("%c",ch);
    }

    fclose(ptr);
    }

    }

Step 2: Save the as open.c (You can give any name)
Step 3: Compile and execute the file.
Step 4: Write click on My computer of Window xp/ vista/ win 7/8.
operating system and select properties.
Step 5: Select Advanced -> Environment Variables
Step 6: Click on new button.
Step 7: Write following:
Variable name: path
Variable value: c:\tc\bin\open.c (the path where you have saved)
Step 8: Open command prompt and write open then file name and press enter button.