A programmer declares the following variables - OCR - GCSE Computer Science - Question 4 - 2021 - Paper 1
Question 4
A programmer declares the following variables.
first = "Computer Science"
second = "is great"
(a) State one difference between a variable and a constant.
(b) Stat... show full transcript
Worked Solution & Example Answer:A programmer declares the following variables - OCR - GCSE Computer Science - Question 4 - 2021 - Paper 1
Step 1
State one difference between a variable and a constant.
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Answer
A variable can change its value during program execution, while a constant has a fixed value that cannot be altered after it is declared.
Step 2
State the output from the following lines of program code.
(i) print(first.length)
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Answer
The output will be 16, which is the number of characters in the string 'Computer Science'.
Step 3
State the output from the following lines of program code.
(ii) print(second.length DIV 3)
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The output will be 2, as the length of the string 'is great' is 8. Performing integer division, 8 DIV 3 equals 2.
Step 4
State the output from the following lines of program code.
(iii) print(3 ^ 2)
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The output will be 9, as 3 raised to the power of 2 (3 squared) equals 9.
Step 5
Use string manipulation with the variables first and/or second to produce the following output.
(i) great
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To produce 'great', you can use: second which contains the string 'is great'. Output: second.substring(3).
Step 6
Use string manipulation with the variables first and/or second to produce the following output.
(ii) Computer
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To output 'Computer', utilize: first.substring(0, 8). This extracts the first 8 characters from the string in first.
Step 7
Use string manipulation with the variables first and/or second to produce the following output.
(iii) Science is great
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To produce 'Science is great', concatenate 'Computer Science'. You can do this by combining parts of first and second: first.substring(4) + " " + second. This outputs 'Science is great'.
