CSED 142: INTRODUCTION

TO

C PROGRAMMING & UNIX

(CSE 142) – HW #4

1. Write a C program to convert a number entered by user to its corresponding month and prints both on the screen, e.g., January for 1. If the number is outside the range of 1 to 12 print appropriate message.
…
int m; printf("Enter a number between 1 and 12:\n"); scanf("%d", &m); switch (m)
{
case 1: printf("January, %d\n", m); break; case 2: printf("February, %d\n", m); break; case 3: printf("March, %d\n", m); break; case 4: …
…
case 12: printf("December, %d\n", m); break; default: printf("please enter a number between 1 and 12.\n");
}
…

2. Design a multiple choice test and prompt the user to enter the correct answer and print appropriate message to let them know whether the answer was correct or not:
Which one of the following is not a type of error?
a) Syntax error
b) Debugging error
c) Runtime error
d) Logic error char c; printf("Which one of the following is not a type of error?\n\n"); printf("\ta) Syntax error\n"); printf("\tb) Debugging error\n"); printf("\tc) Runtime error\n"); printf("\td) Logic error\n"); c = getchar(); switch (c)
{
case 'a': printf("wrong!\n"); break; case 'b': printf("Correct!\n");

break; case 'c': printf("wrong!\n"); break; case 'd': printf("wrong!\n"); break; default: printf("please enter a-d.\n");
}

3.

Show that the sum of the following infinite series converges to π
(3.141592653589793).


(1) n n  0 2n  1

4

int n = 0; double sum = 0; for(n = 0; n < 1000000; n++) sum = sum + 4 * pow(-1,n)/(2*n+1); printf("sum = %lf\n", sum);

4. Taylor expansion can be used to evaluate a function. The following is the Taylor expansion of the exponential function. Write a complete program to compute an approximation to exp(0.9). n 

x

 n! n 0

#include
#include
int factorial(int n); int main(void)
{
int n; double sum = 0; for (n = 0; n