Question: Task B. Counting blocks opened and closed by { and }, and adding real indentation To count open blocks, we need to count how many
Task B. Counting blocks opened and closed by { and }, and adding real indentation
To count open blocks, we need to count how many curly braces get opened and closed on each line, so we need to count { and }
Write a function
int countChar(string line, char c);
that scans the line and returns the number of occurrences of the character c.
Write a new program indent.cpp that enhances the program from the previous task. As it reads the input line by line, it should also count the number of open and closed { } in it, and keep track of how many blocks is currently open at the beginning of each line.
In the listing below, the number of open blocks is shown on the left:
0 int main(){ 1 // Hi, I'm a program! 1 int x = 1; 1 for(int i = 0; i < 10; i++) { 2 cout << i; 2 cout << endl; 2 } 1 } Then instead of printing the number of open blocks, add that number of tabs '\t' at the beginning of each line, and you will get:
int main(){ // Hi, I'm a program! int x = 1; for(int i = 0; i < 10; i++) { cout << i; cout << endl; } // <-- closing for loop } // <-- closing main Notice that the closing curly braces are indented one level further than what they should be.
To fix that, when indenting the line, check its very first character. If it is a closing curly brace }, its indentation level should be reduced by one:
int main(){ // Hi, I'm a program! int x = 1; for(int i = 0; i < 10; i++) { cout << i; cout << endl; } } Shortcomings of our program:
No support for loops and if statements that dont have curly braces. For example,
if (c == 'A') s = s + c;
will be incorrectly indented as
if (c == 'A') s = s + c;
No support for // and /* */. Commented out curly braces should not affect indentation
Symbols {, } inside string and char literals are misinterpreted as blocks
if (true) { s = "\{\{"; t = "ABC"; } will be incorrectly indented as
if (true) { s = "\{\{"; t = "ABC"; } pervious program
#include
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#include
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using namespace std;
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string removeLeadingSpaces(string line);
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int main() { 17
string line;
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while(getline(cin, line)) { 19
cout << removeLeadingSpaces(line) << endl;
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}
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return 0;
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}
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string removeLeadingSpaces(string line) { 25
string result = "";
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bool check = true;
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for(int i = 0; i < line.size(); ++i) { 28
if(!(check && isspace(line[i]))) { 29
result += line[i];
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check = false;
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}
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}
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return result;
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}
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