51) Write a loop statement that will show the following output:
1
12
123
1234
12345
Answer:
for (a=1; a<=5; i++) { for (b=1; b<=a; b++) printf("%d",b); printf("\n"); }
52) What is wrong in this statement? scanf(“%d”,whatnumber);
An ampersand & symbol must be placed before the variable name whatnumber. Placing & means whatever integer value is entered by the user is stored at the “address” of the variable name. This is a common mistake for programmers, often leading to logical errors.
53) How do you generate random numbers in C?
Random numbers are generated in C using the rand() command. For example: anyNum = rand() will generate any integer number beginning from 0, assuming that anyNum is a variable of type integer.
54) What could possibly be the problem if a valid function name such as tolower() is being reported by the C compiler as undefined?
The most probable reason behind this error is that the header file for that function was not indicated at the top of the program. Header files contain the definition and prototype for functions and commands used in a C program. In the case of “tolower()”, the code “#include <ctype.h>” must be present at the beginning of the program.
55) What are comments and how do you insert it in a C program?
Comments are a great way to put some remarks or description in a program. It can serves as a reminder on what the program is all about, or a description on why a certain code or function was placed there in the first place. Comments begin with /* and ended by */ characters. Comments can be a single line, or can even span several lines. It can be placed anywhere in the program.
56) What is debugging?
Debugging is the process of identifying errors within a program. During program compilation, errors that are found will stop the program from executing completely. At this state, the programmer would look into the possible portions where the error occurred. Debugging ensures the removal of errors, and plays an important role in ensuring that the expected program output is met.
57) What does the && operator do in a program code?
The && is also referred to as AND operator. When using this operator, all conditions specified must be TRUE before the next action can be performed. If you have 10 conditions and all but 1 fails to evaluate as TRUE, the entire condition statement is already evaluated as FALSE
58) In C programming, what command or code can be used to determine if a number of odd or even?
There is no single command or function in C that can check if a number is odd or even. However, this can be accomplished by dividing that number by 2, then checking the remainder. If the remainder is 0, then that number is even, otherwise, it is odd. You can write it in code as:
if (num % 2 == 0) printf("EVEN"); else printf("ODD");
59) What does the format %10.2 mean when included in a printf statement?
This format is used for two things: to set the number of spaces allotted for the output number and to set the number of decimal places. The number before the decimal point is for the allotted space, in this case it would allot 10 spaces for the output number. If the number of space occupied by the output number is less than 10, addition space characters will be inserted before the actual output number. The number after the decimal point sets the number of decimal places, in this case, it’s 2 decimal spaces.
60) What are logical errors and how does it differ from syntax errors?
Program that contains logical errors tend to pass the compilation process, but the resulting output may not be the expected one. This happens when a wrong formula was inserted into the code, or a wrong sequence of commands was performed. Syntax errors, on the other hand, deal with incorrect commands that are misspelled or not recognized by the compiler.