Doubt in map and unordered map

can you please help me to understand what a key and value in a map refer to with example

and what dose the below codes mean or imply

int arr[n]
unordered_map<int,int>m
m[a[i]]++; // can you please explain this insertion //
//technique.
//another technique
int x;
while(n–){
cin>>x;
m[x]++, //how is this a hashmap oor a map
}

Hey @adarshsingh2k
So what is key value pair
Say we want to say that ‘abxb’ means 1
‘cjjwj’ means 2 and some othe pairs like this
So we want to map some string to some no

This is where hashmap comes into picture and we use them to do the same.ie mapping of some datatype to some other data type

Another example can be ascii values
Each char have a corresponding ascii value
That can be done using hashmaps as well

So talking about ur code segment

When key is not in map already then its default value is 0 (for int value type)
So in the above line we are simply incrementing the value corresponding to the key a[i] by 1

Again here we are doing the same we are incrementing value corresponding to key x by 1

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use of first and second in maps

Hey @KartikKhariwal
Please share the code and I will answer according to it :slight_smile: