Question

1. Write a program that calculates the frequency of letter occurrences in text.
2. Read ASCII text from standard input.
3. On reaching EOF, print to stdout the normalized frequency of occurrence for each letter a-z that appeared in the input, one per line, in alphabetical order using the format produced by

   printf( "%c %.4f\n", letter, freq);

4. Letters that occur zero times should not appear in the output.
5. Characters other than lower and upper case letters should be ignored.
6. Lower and upper case instances count as the same letter, e.g. 'a' and 'A' are both reported for the letter 'a' on the output.
7. The frequencies reported should sum to approximately 1 (with a little slack for accumulation of printf rounding errors).
8. By the way, you cannot implement this function by writing 26 "if" statements (1 for each letter). Hint: Each letter has a numerical ASCII value. Can this numerical value be used at all?

      Example Runs:

$ ./lfreq
aaab
a 0.7500
b 0.2500

$ ./lfreq
q
q 1.0000

./lfreq < happy_prince.txt
a 0.0841
b 0.0140
c 0.0206
...
y 0.0240
z 0.0002

$ ./lfreq < "large novel in English.txt"
a 0.0817
b 0.0149
c 0.0278
...
y 0.0197
z 0.0001

Language is C. Please avoid the use of break and continue.

Answer 1

Program Files:

Letter Frequency.c

#include <stdio.h>

int main(void)
{
int c;
int alphabet[26];
int temp = 0;
int letterCount = 0;
float freq = 0;
int letter = 0;

for (int x = 0; x < 26; x++)
{
alphabet[x] = 0;
}
int x = 0;

while (c != EOF)
{

c = getchar();
x = 0;
temp = 'a';

if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
{
letterCount++;
}
while (c >= temp && temp >= 'a' && temp <= 'z')
{
if (c == temp)
{
alphabet[x]++;
}
x++;
temp++;
}
temp = 'A';
while (c >= temp && temp >= 'A' && temp <= 'Z')
{
if (c == temp)
{
alphabet[x]++;
}

x++;
temp++;
}
}
letter = 'a';
x = 0;
while (letter >= 'a' && letter <= 'z')
{
if (alphabet[x] != 0)
{
freq = (float)alphabet[x] / (float)letterCount;
printf("%c %.4f\n", letter, freq);
}
x++;
letter++;
}

return 0;
}

output:

 clang-7 main.c
 ./a.out < happy_prince.txt
a 0.0841
b 0.0140
c 0.0206
d 0.0448
e 0.1291
f 0.0199
g 0.0205
h 0.0713
i 0.0661
j 0.0009
k 0.0078
l 0.0540
m 0.0201
n 0.0602
o 0.0714
p 0.0195
q 0.0012
r 0.0536
s 0.0618
t 0.0891
u 0.0237
v 0.0076
w 0.0342
x 0.0005
y 0.0240
z 0.0002

Hope this helps!

Please let me know if any changes needed.

Thank you!