Visual C++ :: Detect ItemID And Delete That Line From File

I have a text file name fruit.txt that contains the following information of fruit id, fruitName and fruitQuantity.

Code:
1:pear:30
2:apple:20
3:banana:24
4:orange:15
5:watermelon:35

If let's say I key in 2, it will search for the id=2 and delete the whole line and the id of banana which is orignially 3, will become 2 and orange which is orignally 4 will become 3 etc.

I researched on how it can be done and most suggested to put inside a vector and fout the line.

I know how to put the values in the vector but how should I go about searching for the id and if the id is found it will delete that line inside the file.

Code:
ofstream fout;
ifstream readFile("fruit.txt");
while (getline(readFile, line)) {

[Code]....