76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <math.h>
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typedef struct{
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double value;
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double delta;
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}imprecise;
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#define SQR(x) ((x) * (x))
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imprecise imprecise_add(imprecise a, imprecise b)
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{
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imprecise ret;
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ret.value = a.value + b.value;
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ret.delta = sqrt(SQR(a.delta) + SQR(b.delta));
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return ret;
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}
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imprecise imprecise_mul(imprecise a, imprecise b)
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{
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imprecise ret;
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ret.value = a.value * b.value;
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ret.delta = sqrt(SQR(a.value * b.delta) + SQR(b.value * a.delta));
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return ret;
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}
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imprecise imprecise_div(imprecise a, imprecise b)
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{
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imprecise ret;
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ret.value = a.value / b.value;
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ret.delta = sqrt(SQR(a.value * b.delta) + SQR(b.value * a.delta)) / SQR(b.value);
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return ret;
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}
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imprecise imprecise_pow(imprecise a, double c)
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{
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imprecise ret;
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ret.value = pow(a.value, c);
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ret.delta = fabs(ret.value * c * a.delta / a.value);
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return ret;
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}
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char* printImprecise(imprecise val)
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{
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char principal[30],error[30],*string,sign[2];
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sign[0] = 241; /* ASCII code for ±, technical notation for denoting errors */
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sign[1] = 00;
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sprintf(principal,"%f",val.value);
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sprintf(error,"%f",val.delta);
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string = (char*)malloc((strlen(principal)+1+strlen(error)+1)*sizeof(char));
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strcpy(string,principal);
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strcat(string,sign);
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strcat(string,error);
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return string;
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}
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int main(void) {
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imprecise x1 = {100, 1.1};
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imprecise y1 = {50, 1.2};
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imprecise x2 = {-200, 2.2};
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imprecise y2 = {-100, 2.3};
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imprecise d;
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d = imprecise_pow(imprecise_add(imprecise_pow(imprecise_add(x1, x2), 2),imprecise_pow(imprecise_add(y1, y2), 2)), 0.5);
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printf("Distance, d, between the following points :");
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printf("\n( x1, y1) = ( %s, %s)",printImprecise(x1),printImprecise(y1));
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printf("\n( x2, y2) = ( %s, %s)",printImprecise(x2),printImprecise(y2));
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printf("\nis d = %s", printImprecise(d));
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return 0;
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}
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