1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
/*
This program will find the roots of one of three different functions on one of
two intervals based on user input.
*/
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
double evaluate(double f(double), double a, double b, double error) {
double mid;
double f_mid;
double f_a = f(a);
double f_b = f(b);
while(fabs(a- b) > error) {
mid = (a+b)/2.0;
f_mid = f(mid);
if(f_mid == 0.0)
{
break;
}
else if((f_mid * f_a) < 0.0)
{
b = mid;
}
else
{
a = mid;
}
}
if (fabs(a-b) == error)
printf("No root found.");
return mid;
}
double func1(double x) {
return (3.0*x*x*x) - (3.0*x*x) + 0.2;
}
double func2(double x) {
return (x*x*x*x) - (3.0*x*x) - 8.0;
}
double func3(double x) {
return 2.0*sin(2.0*x) - 3.0*cos(3.0*x);
}
int main(void)
{
int o, p;
double a, b, error, root, root_value;
printf("Which function do you want to choose (1,2,3): ");
error1:
scanf("%d", &o);
switch ( o ) {
case 1:
printf("Which interval do you want to choose (1,2): ");
error2:
scanf("%d", &p);
printf("What error is accepted (epsilon): ");
scanf("%g", &error);
switch ( p ) {
case 1:
a = -1.0;
b = 0.0;
root = evaluate(func1, a, b, error);
root_value = func1(root);
printf("The root of the function 1 in the interval 1 is %g.\nThe function value at the root is %g\n", root, root_value);
break;
case 2:
a = 0.0;
b = 0.5;
root = evaluate(func1, a, b, error);
root_value = func1(root);
printf("The root of the function 1 in the interval 2 is %g.\nThe function value at the root is %g\n", root, root_value);
break;
default:
printf("ERROR: Enter 1 or 2 for your interval: ");
goto error2;
break;
}
break;
case 2:
printf("Which interval do you want to choose (1,2): ");
error3:
scanf("%d", &p);
printf("What error is accepted (epsilon): ");
scanf("%g", &error);
switch ( p ) {
case 1:
a = -4.0;
b = -2.0;
root = evaluate(func2, a, b, error);
root_value = func1(root);
printf("The root of the function 2 in the interval 1 is %g.\nThe function value at the root is %g\n", root, root_value);
break;
case 2:
a = 2.0;
b = 4.0;
root = evaluate(func2, a, b, error);
root_value = func2(root);
printf("The root of the function 2 in the interval 2 is %g.\nThe function value at the root is %g\n", root, root_value);
break;
default:
printf("ERROR: Enter 1 or 2 for your interval: ");
goto error3;
break;
}
break;
case 3:
printf("Which interval do you want to choose (1,2): ");
error4:
scanf("%d", &p);
printf("What error is accepted (epsilon): ");
scanf("%g", &error);
switch ( p ) {
case 1:
a = 0.0;
b = 1.0;
root = evaluate(func3, a, b, error);
root_value = func3(root);
printf("The root of the function 3 in the interval 1 is %g.\nThe function value at the root is %g\n", root, root_value);
break;
case 2:
a = 1.0;
b = 2.0;
root = evaluate(func3, a, b, error);
root_value = func3(root);
printf("The root of the function 3 in the interval 2 is %g.\nThe function value at the root is %f\n", root, root_value);
break;
default:
printf("ERROR: Enter 1 or 2 for your interval: ");
goto error4;
break;
}
break;
default:
printf("Enter a number between 1 and 3: ");
goto error1;
break;
}
return 0;
}
|
