I'm having an issue removing characters from a string. I have been able to identify the characters to remove and store them as a new string but I would like a code that enables me to remove the new string's characters from the original string (where I've labelled as xxxxxxxx).
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char input[120], to_del[120], new_input[120];
int a,b;
void removeString();
int main(void)
{
printf("\nEnter your sentence: ");
gets(input);
printf("\nWhere to start: ");
scanf("%d",&a);
printf("\nHow many characters to delete: ");
scanf("%d",&b);
removeString();
printf("\nNew sentence: %s\n",new_input);
return ;
}
void removeString()
{
memcpy(to_del, &input[a-1], b);
new_input [strlen(input)-b] =xxxxxxxx;
return ;
}
EDIT in response to @SouravGhosh comment, about overlapping strings. First I copy the string to new_input and then copy the right hand part back to input to overwrite the section which must be removed.
int len = strlen(input);
strcpy(new_input, input);
if (a < len && a+b <= len)
strcpy (input + a, new_input + a + b);
I notice the rest of your code doesn't check anything is happening correctly, such as the return value from scanf, and please note gets is dangerous: it is better to use fgets with stdin.
The strcpy instruction copies the right-hand part of the string over the part you want removed. It works by using pointer arithmetic. Adding a to input is the same as getting the address of input[a], the place where you want the removal to begin. Similary new_input[a+b] is the start of the right hand part you wish to keep.
The point of the if condition, is that if a isn't within the string, or if the part you want removed overflows the end of the string, it can't be done.