C语言K&R习题系列——统计一段文字中各个字母出现的频率

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原题：

/*Write a program to print a histogram of the frequencies of

*difficent characters in it inputs

这个和上一个类似

输入部分

#include < stdio.h >   #define NUM_CHARS 256   main ( void ) {    int c;    int done = 0;    int thisIdx = 0;    long frequrr[NUM_CHARS + 1];    long thisVal = 0;    long maxVal = 0;    //initialize    for ( thisIdx = 0; thisIdx <= NUM_CHARS; thisIdx++ )    {        frequrr[thisIdx] = 0;    }         while ( done == 0 )    {        c = getchar();                 if ( c == EOF )        {            done = 1;        }                 if ( c < NUM_CHARS )        {            thisVal = ++frequrr[c];            if ( thisVal > maxVal )            {                maxVal = thisVal;            }        }        else         {            thisVal = ++frequrr[NUM_CHARS];            if ( thisVal > maxVal )            {                maxVal = thisVal;            }        }    }

输出部分

for ( thisVal = maxVal; thisVal >0; thisVal-- )    {        printf ( "%2d |", thisVal );        for ( thisIdx = 0; thisIdx <= NUM_CHARS; thisIdx++ )        {            if ( frequrr[thisIdx] >= thisVal )            {                printf ( "*" );            }            else if ( frequrr[thisIdx] > 0 )            {                printf ( " " );            }        }        printf ( "\n" );    }    printf ( "   |_" );    for ( thisIdx = 0; thisIdx < NUM_CHARS + 1; thisIdx++ )    {        if ( frequrr[thisIdx] > 0 )        printf ( "_");    }    printf ( "\n    " );    for ( thisIdx = 0; thisIdx < NUM_CHARS + 1; thisIdx++ )    {        if ( frequrr[thisIdx] > 0 )        printf ( "%d", ( thisIdx + 1 ) / 100 );    }    printf ( "\n    " );    for ( thisIdx = 0; thisIdx < NUM_CHARS + 1; thisIdx++ )    {        if ( frequrr[thisIdx] > 0 )        printf ( "%d", ( thisIdx + 1 ) / 10 % 10 );    }    printf ( "\n    " );    for ( thisIdx = 0; thisIdx < NUM_CHARS + 1; thisIdx++ )    {        if ( frequrr[thisIdx] > 0 )        printf ( "%d", ( thisIdx + 1 ) % 10 );    }    printf ( "\n" );    return 0; }

运行结果

1 0