Learn to Program with C_ Learn to Program using the Popular C Programming Language ( PDFDrive )

Chapter 10 ■ Structures
else
print invalid vote
add 1 to spoiltVotes
endif
get a vote
endwhile
After all the votes are processed, this function will need to return the number of valid and
spoiled votes. But how can a function return more than one value? It can, if the values are stored
in a structure and the structure returned as the “value” of the function.
We will use the following declaration:
typedef struct {
int valid, spoilt;
} VoteCount;
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And we will write processVotes as follows:
VoteCount processVotes(PersonData person[], int max, FILE *in, FILE *out) {
VoteCount temp;
temp.valid = temp.spoilt = 0;
int v;
fscanf(in, "%d", &v);
while (v != 0) {
if (v < 1 || v > max) {
fprintf(out, "Invalid vote: %d\n", v);
++temp.spoilt;
}
else {
++person[v].numVotes;
++temp.valid;
}
fscanf(in, "%d", &v);
} //end while
return temp;
} //end processVotes
Next, we write main, preceded by the compiler directives and the structure declarations.
#include <stdio.h>
#include <string.h>
#define MaxCandidates 7
#define MaxNameLength 30
#define MaxNameBuffer MaxNameLength+1
typedef struct {
char name[MaxNameBuffer];
int numVotes;
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