#include<stdio.h>
#include<stdlib.h>
#include<string.h>
void fun(char *fname,char *st)
{
    FILE *myf;
    int i;

    myf=fopen(fname,"w");

    for(i=0;i<strlen(st);i++)
        fputc(st[i],myf);
    fclose(myf);
    myf=fopen("fname","r");
    for(i=0;i<strlen(st);i++)
        printf("%c",st[i]);
    printf("\n");
    fclose(myf);
}

void main()
{
    fun("test.txt","new world");
    fun("test.txt","hello");
}

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
void fun(char *fname,char *st)
{
    FILE *myf;
    unsigned int i;

    myf=fopen(fname,"w");

    for(i=0;i<strlen(st);i++)
        fputc(st[i],myf);
    fclose(myf);
    myf=fopen("fname","r");
    for(i=0;i<strlen(st);i++)
        printf("%c",st[i]);
    printf("\n");
    fclose(myf);
}

void main()
{
    fun("test.txt","new world");
    fun("test.txt","hello");
}