Question

C programing language

1. A file "data.txt" contains only integers. Write a code to find average of all values and print the average
2. How would you use execlp function to execute "ps –e –a –l" command
3. char *dt = "The five boxing wizards jump quickly";

1. write a program to count frequency of each letter, ignore case. Print the letter and frequency of each letter.

// 1A: . Ask the user to enter a password string, store it in pass. Password should contain atleast one Upper case, one Lower case letter , one of the 0-9 digits

Answer 1

(1)

#include<stdio.h>
int main(){
   FILE*fptr;
   fptr = fopen("data.txt","r");
   double sum=0;
   int count=0,value;
  
   while(fscanf(fptr, "%d", &value) != EOF){
       count++;
       sum+=value;
   }
  
   printf("Average value : %d\n",sum/value);
   fclose(fptr);
   return 0;
}

(2)

#include<stdlib.h>

int main(){
   char *dt = "The five boxing wizards jump quickly";
   int count[26],i;
   for(i=0;i<26;i++)count[i] = 0;
  
   i=0;
   while(dt[i] != '\0'){
       char ch = dt[i++];
       if(ch >= 'A' && ch <='Z')count[ch-'A']++;
       if(ch >= 'a' && ch <='z')count[ch-'a']++;
   }
  
   for(i=0;i<26;i++){
       if (count[i]!=0)printf("%c-%d\n",(i+'a'),count[i]);
   }
   return 0;
}

(3)

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

int main(){
   char password[25];
   int upper,lower,digit,i;
  
  
   while(1){
       upper=0;lower=0;digit=0;
       printf("Enter password : ");
       scanf("%s",password);
  
       for(i=0;i<strlen(password);i++){
           char ch = password[i];
           if(ch>='A' && ch<='Z')upper++;
           if(ch>='a' && ch<='z')lower++;
           if(ch>='0' && ch<='9')digit++;
       }
      
       if(upper>0 && lower>0 && digit>0)break;
       else{
           printf("Invalid password. Re-enter Password\n");
       }
   }
  
   printf("\nPassword : %s",password);
   return 0;
}