include <bits/stdc++.h>
using namespace std;
 
class Process {
private:
    int at;
    int bt;
    int ct;
    int tat;
    int wt;
    int pid;
 
public:
    int& operator[](string var)
    {
        if (var == "at")
            return at;
        if (var == "bt")
            return bt;
        if (var == "ct")
            return ct;
        if (var == "tat")
            return tat;
        if (var == "wt")
            return wt;
        return pid;
    }
 
    void update_after_ct()
    {
        tat = ct - at;
        wt = tat - bt;
    }
 
    void display()
    {
        printf("%d\t%d\t%d\t%d\t%d\t%d\n", pid, at, bt, ct,
               tat, wt);
    }
};
 
float average(vector<Process> P, string var)
{
    int total = 0;
    for (auto temp : P) {
        total += temp[var];
    }
    return (float)total / P.size();
}
 
int main()
{
    /*
    Input description.
    First line contains an integer n
    the next n lines contains 2 space separated integers
    containing values for arrival time and burst time for
    example:
    2
    0 3
    1 2
    */
    int n;
    cin >> n;
    int counter = 0;
    vector<Process> P(n);
    for (Process& temp : P) {
        temp["id"] = counter++;
        cin >> temp["at"] >> temp["bt"];
    }
    sort(P.begin(), P.end(),
         [](Process first, Process second) {
             return first["at"] < second["at"];
         });
    printf("pid\tat\tbt\tct\ttat\twt\n");
    P[0]["ct"] = P[0]["at"] + P[0]["bt"];
    P[0].update_after_ct();
    P[0].display();
    for (int i = 1; i < P.size(); i++) {
        if (P[i]["at"] < P[i - 1]["ct"]) {
            P[i]["ct"] = P[i - 1]["ct"] + P[i]["bt"];
        }
        else {
            printf("curr['at'] : %d, prev['ct'] : %d\n",
                   P[i]["at"], P[i - 1]["ct"]);
            P[i]["ct"] = P[i]["at"] + P[i]["bt"];
        }
        P[i].update_after_ct();
        P[i].display();
    }
 
    printf("Average waiting time : %f\n", average(P, "wt"));
    return 0;
}
by

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#include <stdio.h>
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    scanf("%s", name);
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    return 0;
    
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About C

C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.

Key features:

  • Structured Programming
  • Popular system programming language
  • UNIX, MySQL and Oracle are completely written in C.
  • Supports variety of platforms
  • Efficient and also handle low-level activities.
  • As fast as assembly language and hence used as system development language.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition if-else is used.

if(conditional-expression) {
   // code
} else {
   // code
}

You can also use if-else for nested Ifs and if-else-if ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to if-else-if ladder.

switch(conditional-expression) {    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
...    
    
default:     
 // code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  // code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition) {  
 // code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {
  // code 
} while (condition);

Arrays

Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.

Syntax

One dimentional Array:

data-type array-name[size];

Two dimensional array:

data-type array-name[size][size];

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.

Two types of functions are present in C

  1. Library Functions:

Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,

  1. User defined functions:

User defined functions are the ones which are written by the programmer based on the requirement.

How to declare a Function

return_type function_name(parameters);

How to call a Function

function_name (parameters)

How to define a Function

return_type function_name(parameters) {  
  //code
}