parser.c

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

void parser(char * string)
{
    int in=0; //Variable to track whether we are inside the tag
    int index = 0;
    for (int i = 0; i < strlen(string); i++){
        if(string[i] == '<'){
            in = 1;
            continue;
        }
        else if(string[i]=='>')
        {
            in = 0;
            continue;
        }
        if(in==0){
            string[index] = string[i];
            index ++;
        }
    }
    string[index] = '\0';
    //Remove the trailing spaces from the beginning
    while(string[0] ==' ')
        for (int i = 0; i < strlen(string); i++)  
            string[i] = string[i+1];  //Shift the string to the left
    //Remove the trailing spaces from the end
    while(string[strlen(string) - 1] == ' ')
        string[strlen(string) - 1] = '\0';
}

int main()
{
    char string[] = "    <harrysdfsdfsdf>this is a heading    </harry>     ";
    parser(string);
    printf("The parsed string is ~~%s~~", string);
    return 0;
}
/*
Input:
<h1> This is a heading </h1> 

Output:
This is a heading

Input:
<span> This is a heading2 </span> 

Output:
This is a heading2
*/