C Programming Day-10

1. What is the correct function to calculate the square root of a number in C?

• sqrt()

• pow()

• sqr()

• root()

Answer explanation

sqrt() returns the square root of a number. You must include math.h.

What does the function pow(2, 3) return?

• 5

• 6

• 7

• 8

Answer explanation

pow(a, b) returns a raised to the power b.

Which of the following functions returns the absolute value of a number?

• mod()

• absval()

• fabs()

• abs()

Answer explanation

For integers, the correct function is abs() (from stdlib.h)

For floating-point numbers, use fabs() (from math.h)

Which header file is needed for using ceil() and floor() functions?

• stdio.h

• stdlib.h

• math.h

• string.h

Answer explanation

ceil() gives the smallest integer ≥ number; floor() gives the largest integer ≤ number.

What does floor(3.8) return?

• 4.0

• 3.5

• 3.8

• 3.0

Answer explanation

floor() rounds down to the nearest integer.

What does strlen("hello") return?

• 5

• 4

• Error

• 6

Answer explanation

strlen() counts characters in a string (excluding \0).

Which function is used to copy one string into another?

• strcat()

• strcpy()

• strlen()

• strrev()

Answer explanation

strcpy(destination, source) copies the source string into destination.

What is the output of strcmp("abc", "abc")?

• 1

• 0

• -1

• Error

Answer explanation

strcmp() returns 0 if strings are equal.

What does strcat("Hello", "World") do?

• Joins the strings and stores in the first string's memory

• Throws an error

• Compares the strings

• Joins the strings and stores in a new variable

Answer explanation

strcat(dest, src) appends src to dest.

Which function is used to find a substring in a string?

• strchr()

• strstr()

• strlen()

• strcpy()

Answer explanation

strstr(main_str, sub_str) returns a pointer to the first occurrence of the substring.