How to read a text file by c program

#include<stdio.h>

int main(){

char str[70];

FILE *p;

if((p=fopen("string.txt","r"))==NULL){

printf("\nUnable t open file string.txt");

exit(1);

}

while(fgets(str,70,p)!=NULL)

puts(str);

fclose(p);

return 0;

}