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UPLOW.C
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C/C++ Source or Header
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1987-11-21
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1KB
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43 lines
/* Chapter 13 - Program 1 */
#include "STDIO.H"
#include "ctype.h" /* Note - your compiler may not need this */
main()
{
FILE *fp;
char line[80], filename[24];
char *c;
printf("Enter filename -> ");
scanf("%s",filename);
fp = fopen(filename,"r");
do {
c = fgets(line,80,fp); /* get a line of text */
if (c != NULL) {
mix_up_the_chars(line);
}
} while (c != NULL);
fclose(fp);
}
mix_up_the_chars(line) /* this function turns all upper case
characters into lower case, and all
lower case to upper case. It ignores
all other characters. */
char line[];
{
int index;
for (index = 0;line[index] != 0;index++) {
if (isupper(line[index])) /* 1 if upper case */
line[index] = tolower(line[index]);
else {
if (islower(line[index])) /* 1 if lower case */
line[index] = toupper(line[index]);
}
}
printf("%s",line);
}