1 | #include <stdio.h>
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2 |
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3 | #define RINGBUFFER_SIZE 9
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4 | #define INVALID_VALUE -1000
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5 | #define LAST_MEAN_VALUES 3
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6 |
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7 | int RingBuffer[ RINGBUFFER_SIZE ];
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8 | int RingBufferCurrent; // zeigt an, wo der nächste Wert abgelegt wird
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9 |
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10 | void InitRingBuffer( void )
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11 | {
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12 | unsigned char i;
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13 |
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14 | RingBufferCurrent = 0;
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15 | for( i = 0; i < RINGBUFFER_SIZE; ++i )
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16 | RingBuffer[i] = INVALID_VALUE;
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17 | }
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18 |
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19 | void AddValue( int Value )
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20 | {
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21 | RingBuffer[RingBufferCurrent++] = Value;
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22 | if( RingBufferCurrent == RINGBUFFER_SIZE )
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23 | RingBufferCurrent = 0;
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24 | }
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25 |
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26 | int MeanValue( void )
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27 | {
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28 | unsigned char i;
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29 | unsigned char nrValues = 0;
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30 | long Summ = 0;
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31 |
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32 | for( i = 0; i < RINGBUFFER_SIZE; ++i ) {
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33 | if( RingBuffer[i] != INVALID_VALUE ) {
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34 | Summ += RingBuffer[i];
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35 | nrValues++;
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36 | }
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37 | }
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38 |
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39 | if( nrValues == 0 )
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40 | return INVALID_VALUE;
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41 |
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42 | return Summ / nrValues;
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43 | }
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44 |
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45 | int MeanValueOfLast( void )
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46 | {
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47 | long Summ = 0;
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48 | unsigned char i = RingBufferCurrent;
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49 | unsigned char nrValues = 0;
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50 |
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51 | do {
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52 | if( i == 0 )
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53 | i = RINGBUFFER_SIZE - 1;
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54 | else
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55 | --i;
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56 |
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57 | if( RingBuffer[i] != INVALID_VALUE ) {
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58 | Summ += RingBuffer[i];
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59 | nrValues++;
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60 | }
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61 | } while( nrValues != LAST_MEAN_VALUES && i != RingBufferCurrent );
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62 |
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63 | if( i == RingBufferCurrent )
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64 | return INVALID_VALUE;
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65 |
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66 | return Summ / nrValues;
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67 | }
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68 |
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69 | void PrintValues( void )
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70 | {
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71 | unsigned char i = RingBufferCurrent;
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72 |
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73 | printf( "Buffer: " );
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74 | do {
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75 | if( RingBuffer[i] != INVALID_VALUE )
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76 | printf( "%d ", RingBuffer[i] );
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77 |
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78 | i++;
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79 | if( i == RINGBUFFER_SIZE )
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80 | i = 0;
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81 | } while( i != RingBufferCurrent );
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82 | printf( "\n" );
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83 | }
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84 |
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85 |
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86 | int main()
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87 | {
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88 | InitRingBuffer();
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89 |
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90 | PrintValues();
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91 | printf( "%d %d\n", MeanValue(), MeanValueOfLast() );
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92 |
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93 | AddValue( 5 );
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94 | PrintValues();
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95 | printf( "%d %d\n", MeanValue(), MeanValueOfLast() );
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96 |
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97 | AddValue( 7 );
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98 | PrintValues();
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99 | printf( "%d %d\n", MeanValue(), MeanValueOfLast() );
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100 |
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101 | AddValue( 9 );
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102 | PrintValues();
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103 | printf( "%d %d\n", MeanValue(), MeanValueOfLast() );
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104 |
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105 | AddValue( 11 );
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106 | PrintValues();
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107 | printf( "%d %d\n", MeanValue(), MeanValueOfLast() );
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108 |
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109 | AddValue( 20 );
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110 | AddValue( 20 );
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111 | AddValue( 20 );
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112 | AddValue( 20 );
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113 | AddValue( 20 );
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114 | AddValue( 20 );
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115 | AddValue( 20 );
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116 |
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117 | PrintValues();
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118 | printf( "%d %d\n", MeanValue(), MeanValueOfLast() );
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119 | }
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